Let's start with Jaskier again.
"Geralt! Hello. What's it been, months? Years? What is time, anyway? I heard you were in town. Are you following me, you scamp? I mean, I'm flattered and everything, but you should really think about getting a hobby one of these days."
This is the third of Jaskier's four episodes. The first time he appears, he acts bold but there's definitely an aspect of putting on a front given how nervy he acts after getting punched. He's a lot more confident the next time - he does have to bully Geralt into coming to the banquet with him, but he doesn't hesitate to do things that annoy Geralt, even down to taking the drink from his hand, so he's certain Geralt will do it.
This time? I think Jaskier's uncomfortable. I think at least as far as he knows, Geralt doesn't ever seek him out. Either he makes excuses for that (Geralt does go places because Jaskier's there but always pretends it was a coincidence) or he's been ignoring it. It could be that this has been an ever-growing source of anxiety for Jaskier that's only coming out now because of an additional rejection pushing it over the edge, or it could be that Jaskier really was fine with it because he was feeling generally confident in himself but he's now questioning if he was right.
Either way, what's about to play out has a lot to do with the countess.
Jaskier: (takes a swig of mystery liquid, because Jaskier is drunk and set on staying that way.) "Ugh! Do you want some? "How are you doing?" I hear you ask."
Geralt: "I didn't."
Jaskier: "Well, the Countess de Stael, my muse and beauty of this world, has left me. Again. Rather coldly and unexpectedly, I might add."
Jaskier is upset about this. Now "left me. Again." paints a picture of an on-again, off-again relationship, where this sort of thing isn't necessarily such a big deal, and his whole "my muse and beauty of this world" thing is so over the top it wraps around to a joke.
But "Rather coldly and unexpectedly, I might add." is, I think, key. It's not at all a joke. Jaskier doesn't know why she got sick of him. He didn't see it coming. He's badly hurt.
And this is where OTP purity fixations cause a problem. Though the countess is only relevant for how this is going to impact the relationship between the two of them, it still requires Jaskier to have a relationship with the countess that he was invested in and is hurt over losing. If you want to make the countess solely about Geralt/Jaskier, Jaskier's side of this falls apart. The countess can't have not been a relationship, because then he wouldn't care why. The countess can't have dumped Jaskier because he wouldn't stop mooning over Geralt, because then he'd know why. She definitely can't have nobly given her blessing to the two of them and sent Jaskier on his way, because then he'd not only know why but be happy about it.
In order for Jaskier's other relationships to impact his relationship with Geralt, he has to be allowed to have other relationships. Remove that, and Jaskier's upcoming behavior here would be inexcusably awful. Really, even what he's done already would be inexcusably awful, because Geralt is also a mess right now and the only thing that excuses Jaskier missing it is that he's wrapped up in his own misery.
Now, will Jaskier himself admit that? No.
Jaskier: "I fear I shall die a brokenhearted man. Or a hungry one, at the very least, unless somebody fancies sharing a fish with an old friend?"
Jaskier tries to minimize how upset he is about what happened. It's unclear if Jaskier's the kind of person who does it because he needs some indication from the other person that he's allowed to be admit he actually is pretty hurt before he goes further or if Jaskier would be doing this little song and dance regardless because he prefers handling things by acting like it's fine and moving on to the next distraction.
Jaskier: "Oh, are we not using "friend"? Yeah, sure. Let's just give it another decade."
Either way, what Jaskier can't take right now is the idea Geralt doesn't care about him either. And that's going really badly. Jaskier is sensitive enough he'd probably be second-guessing even a normal interaction, and this isn't a normal interaction because Jaskier's being unusually vulnerable, but Geralt is still brushing him off.
Now, one problem with how few episodes we have is we don't know if this is the first time Jaskier's tried to ask for any sign Geralt doesn't hate him. You could easily argue that Geralt is acting the same way he always does and it's just that's not good enough for Jaskier. On the other hand, Geralt's under a lot of stress of his own, and he's certainly about to do something unusual on his end. I think it's quite possible they do get along better at times, because, "the Countess de Stael, my muse and beauty of this world, has left me. Again. Rather coldly and unexpectedly, I might add." is a situation where a relationship he thought was okay went sour. So if Geralt is acting more coldly toward him than usual, that's precisely in line with a fear that people get sick of him.
That said, we can tell even if Geralt is normally a bit warmer, he's never called Jaskier his friend. I think it's pretty plausible Geralt would normally hand over a fish and Jaskier could take that to be a sign, but because he's not actually fishing, he doesn't do that either.
(As an aside, for those trying to keep track of the timeline, "let's just give it another decade" establishes that at least one decade has already passed, and while it isn't solid, I guessed it meant that the next time we'd have reached the second decade because it's bringing up the idea of seeing how things look two decades in.)
Despite how badly this is all going, Jaskier does manage to pull out of it rather than let it get worse!
"Geralt, you're fantastic at a great many things, but clearly, fishing is not one of them. Have you caught anything today? What are you fishing for, exactly? Is it cod? Carp? Pike? Bream? I'm just-- I'm just listing fish that I know. Zander? Is that a fish?"
He seems to have registered that he shouldn't feel too rejected Geralt didn't offer him a fish because Geralt doesn't have any fish. He may also be assuming that if Geralt really doesn't want him around, he'll be punched (I'd hope that by now he's worked out what actually happened there, but given fandom missed it despite being able to replay the exact scene, something human brains can't do with things they merely lived through, it's completely believable he never re-evaluated what happened there) so the fact he's been chattering away at Geralt this long without a definite rejection is still enough to make him feel a bit better.
As a side note, he doesn't seem to know much about nature if he just lists a couple random fish. On the other hand: he's drunk, so it's not definite proof sober Jaskier also only knows four and a half fish.
Geralt: "I'm not fishing. I can't sleep."
Jaskier: "Right. Good. Well, that-- that makes sense. Insomuch that it sort of...doesn't. What's going on, Geralt? Talk to me."
This is a very interesting exchange, I think.
I argued that Jaskier's fourth episode behavior was not him doing a particularly good job at the whole friendship thing. How much of that, though, is that Geralt is usually too guarded for Jaskier to have any opportunity?
It took Jaskier a bit to realize Geralt was acting odd - again, Jaskier's drunk - but as soon as it does register, he drops his own problems and offers to help.
And Geralt actually takes him up on it, a bit. Geralt explains he's looking for the djinn, which, unfortunately, Jaskier doesn't take very seriously - but once again, drunk. I think we should judge Jaskier by the well-meant attempt rather than the fumbled execution.
Jaskier: "I don't mean to play priest's ear or anything, but has it occurred to you that maybe we're merely rubbing salve on a tumor? Not exactly addressing the root cause of the problem?"
Geralt: "Hm?"
Jaskier: "I mean, maybe, just-- just maybe, this whole sleeplessness-ness has got something to do with what the druid Mousesack said to you in Cintra? You know, the Law of Surprise? Destiny? Being unable to escape the child that belongs to you, et cetera, et cetera?"
Geralt: "No! It's not that."
Jaskier: "Yeah, you're probably right. But what if you're not?"
Not only is Jaskier sincerely trying to help with what Geralt's upset about, but it also shows how much attention he pays to Geralt. Jaskier's referencing the events of the banquet at the time, not any more recent conversation about it. This was years ago, but Jaskier picked up on, and remembers now, amid all the chaos of the actual events, how someone else said things to Geralt implying that Geralt was really distressed about the child surprise thing, and he works out it's probably been weighing on Geralt the whole time.
So, what Geralt said to Jaskier in the bath didn't get through but what Mousesack said about Geralt did. Unfortunately, the two situations are so different I don't think we can tell anything more precise there other than that Jaskier sometimes doesn't understand what's going on with Geralt and sometimes he does. That said, possible factors:
1) Something Jaskier really didn't want to hear vs something he had no such personal investment in, as "I'm going to die a miserable death" is a lot harder to swallow than, "Oh fuck, I'm not ready to be a father".
2) Third party rather than the person. This very conversation shows that Jaskier himself is not a very reliable narrator of his own feelings, and he also feels he personally is a better judge of Geralt so why wouldn't another of Geralt's friends be more accurate than Geralt himself?
3) Jaskier being more easily able to put himself in Geralt's shoes when it comes to surprise child anxiety - I doubt he'd be in near this amount of stress over it, but I'm sure it's not that hard to imagine being uncomfortable to suddenly be a dad and even more so when you're co-parenting with a mass murdering queen who has established she's extra enthusiastic about murdering anyone who thinks they have a claim to her family members.
(Also if Jaskier was eavesdropping on the final conversation between Geralt and Mousesack, he knows Geralt had no issue calling Mousesack his friend. Quite possibly his bit about "Let's just give it another decade." is not just a general discomfort but him wondering if that's actually the issue, that Geralt is the sort of person who thinks you have to know someone for a long time first and he's not interested in adjusting that timetable to take into account that Jaskier's human.)
Jaskier: "You know, the Countess de Stael once said to me that destiny is just the embodiment of the soul's desire to grow.
Geralt: "Did you sing to her before she left?"
Jaskier: "I did, actually, and she...Why, what are you implying? Oh... (laughs) We are so having this conversation. Come on, Geralt. Tell me. Be honest. How's my singing?"
Geralt: "It's like ordering a pie and finding it has no filling."
Ah, the pie exchange.
This is absolutely not Geralt stealth saying he actually loves Jaskier's singing because he prefers crust. Among other things, what sort of raging asshole says something that's technically true in such a way that it's going to be misinterpreted like that? And we know full well at this point that Geralt does not value honesty in conversations, technical or otherwise. He says whatever works.
Does the simile have any other deeper meaning?
Probably not, honestly. I say this at over 100k words into every bit of meaning I can wring out of this show. But look at Jaskier's reaction:
"You need a nap! I mean, are you trying to hurt my feelings, Geralt? It's... It's down-- downright indecorous of you, if I'm completely honest, and--"
Jaskier not only asks for and has no issue with Geralt's second episode criticism, but also gets pelted by food as people scream at him to shut up and takes that fine. I don't think his bad reaction here is down to being in a worse mental place. He's outraged because he knows Geralt is intentionally kicking him while he's down for the sake of it. Geralt paused and thought of exactly what to say to upset Jaskier and then he said it. And he's doing this in response to Jaskier showing concern for him and trying to help.
Which leads, quite understandably, into Jaskier going for the bottle.
Geralt: "The djinn."
Jaskier: "Do you mind if I-"
Geralt: "Jaskier."
Jaskier: "Take it back about my fillingless pie. Take it back, you get your djinny-djinn-djinn."
Jaskier is not upset about if his singing is bad. I'm sure he's not feeling great about it, but this isn't a reaction to Geralt not liking his singing, because an actual feeling can't be taken back. He's demanding Geralt admit that he was being a dick and apologize for that.
But then it seems like there is a djinn! And Jaskier goes for that instead.
"Djinn, I have freed thee, and as of this day, I am thy lord. Firstly, may Valdo Marx, the troubadour of Cidaris, be struck down with apoplexy and die. Secondly, the Countess de Stael must welcome me back with glee, open arms and very little clothing."
We know nothing about Valdo Marx and possibly the guy actually deserves it, but I will say that it's a rather damning Jaskier identifies him as "the troubadour of Cidaris" and not "that wife-beating asshole" or such, as if Jaskier's beef with him is tied to his profession/status and not any legitimate crimes he's committed. Also, if Jaskier thought to use the wishes to kill actual horrible people, you'd think he someone as well-traveled as Jaskier would be able to think of more than just one person.
I previously drew a comparison between his second wish and the orgy, but to elaborate, I think magic like this is not really comparable to any real-world thing. "Glee" especially suggests Jaskier is not aiming for the countess to be puppetted through the motions against her will or otherwise made miserable by this, and the "Again" means he has reason to not think the dumping was intended as a permanent thing in the first place, since she's changed her mind before. Where, on the roofies to normal sudden infatuation scale, does this fall? In a setting with established love potions I'd expect people to have thought this through (and to have enough people with first-hand experience to form a consensus) but that doesn't appear to be true here, so Jaskier isn't asking for something he'd know was harmful. He's just saying something selfish, and in a way that continues to reinforce the fact that he's upset about what happened and doesn't understand why it happened (he doesn't wish to undo a fight they had, or make her like something about him she hated, or otherwise actually solve the reason for it, he just wants things back like they were).
But these are not good wishes. Possibly they're not even the kind of wishes he'd be making on a better day, he might not even be taking them seriously because he's still pretty sure djinns aren't real and he's just being annoying here, and certainly they are deeply unwise - there is no way, at all, that this is Jaskier helpfully trying to burn through the wishes before Geralt makes a dangerous wish of his own. (They're also far too lengthy if Jaskier's plan was to prevent Geralt from making wishes. Seriously, just accept he really is just making wishes.)
Jaskier: "Thirdly-"
Geralt: "Jaskier!"
Jaskier: "Wha-"
Geralt: "Stop! There are only three wishes."
Jaskier: "Oh, come on, you always say you want nothing from life. How was I to know you wanted three wishes all to yourself?"
This is the point at which Jaskier's definitely flipped trying to interpret Geralt in a positive a light to a negative one. Geralt waited for Jaskier to say two wishes and intervenes only on the third, but Jaskier responds by saying Geralt's demanding all three wishes. He is really, really mad about the pie thing, and no, it's not the particular metaphor, it's that Geralt still hasn't apologized - either he didn't realize Geralt waited to let him have those wishes and thinks he just got them out too fast for Geralt to react, or, just as Jaskier shows affection largely through words rather than actions, he's also much better at understanding the word kind and he's just too caught up in waiting for Geralt to say something to consider what it means that Geralt let him make two wishes without issue.
In response to Jaskier's really unfair accusation of Geralt demanding all wishes after he let Jaskier have most of them, Geralt, at the very end of his rope, shouts he wants peace, and Jaskier finds himself choking.
And really? The blame goes to Jaskier here. He got into a fight over the jar, then was shouting wishes, then he capped that all off with shouting more at Geralt who he knew was in a bad way until Geralt snapped at him and said something that accidentally triggered the djinn - Geralt doesn't even use the word "wish" when he says it, let alone say anything that could be reasonably interpreted as targeted at Jaskier. It's not only an accident, but Geralt isn't even behaving in an irresponsible way. At most, we could argue that if Geralt was aware djinns twist wishes he should've been more careful about saying anything, but not only did Geralt not believe he had control of the djinn so he lacked any reason to be watching his words, but also, his actions throughout are in line with someone who doesn't actually know much about djinns. I don't think he'd have let Jaskier start on a first wish without giving him a warning if he knew it was important to rules-lawyer everything you say.
At this point, with neither of them knowing Geralt even did anything there, Geralt throws himself into trying to find help for Jaskier. Jaskier's still lucid at this point.
Chireadan: "He could die."
Jaskier: "Fuck! Geralt."
Geralt: "Uh...Yeah, we won't let that happen."
I understand some people find this a bad response from Geralt. It's also completely in line with Geralt's normal behavior. If Jaskier, after knowing him for more than a decade and knowing this is him sincerely saying he will make sure Jaskier's okay no matter what it takes, thinks that's not good enough, then they probably shouldn't be friends because at a certain point you're really saying, "I'd like you if only you were somebody else entirely."
Luckily for the actual characters, Jaskier seems to find this perfectly acceptable. We know he's following the conversation with Chireadan, and he seems lucid all the way to Yennefer. He doesn't put up any fuss as Geralt carts him around, evidently trusting that whatever is happening, Geralt is going to make things work. It's possible he doesn't remember all of the events, but it seems most likely he's only confused about what happens after he goes unconscious.
The events that occur next, which Jaskier probably remembers:
More horse riding because Geralt's rushing.
Geralt assaulting a man for getting in their way.
Geralt carting him into the building.
Geralt bringing him to the mage and making a deal with her. - "Fix it, and I'll pay you. Whatever the price."
After this, Jaskier is unconscious, a lot of stuff happens, and then he wakes up.
"Oh! Where am I? Whew! Um... Right. Good. Good. Um... Not to be... untoward or anything... but... ...did we... you know... ...do the, uh... Ooh, Go-- Oh, no! No! Definitely did not butter that biscuit. Look, I am so sorry, but I've just remembered I left my...cat on the...stove. I-- I really must be going."
Jaskier seems to know immediately that Yennefer is bad news. He doesn't seem particularly cheery about waking up in bed to see a half-dressed woman, and as soon as he sees her face he moves from uncertain to terrified. Why, exactly? Most likely, it's down to Jaskier having a pretty good idea of how people normally act and reacting to the fact Yennefer's behavior isn't just intentionally threatening but also really off - and someone acting in ways you don't understand and which are very unusual is dangerous. The main thing that's odd is how fast Jaskier reacts, but Jaskier has experience needing to flee situations and is smart/shameless enough, I think, that he's not going to pretend to be comfortable because it'd be rude to react badly on little evidence. He trusts his gut.
At any rate, Jaskier fears and hates Yennefer on sight. She's about to hold a knife to his dick and it does little to escalate things because Jaskier went from zero to max panic just from Yennefer herself. Some of this reaction appears to be startlingly accurate - she's about to hold a knife to his dick, after all. Some of it doesn't - Jaskier believes she'd kill him, but going by what Geralt says, she could've killed him while he was still asleep. I suspect one issue could be that Yennefer wants to present herself as terrifying and is trying to add in extra to counterbalance the fact she feels people tend toward dismissing her, while Jaskier does not have any hangups about being afraid of her, so she's overshot. He might also be picking up on incongruities in how she's presenting herself but is assuming that if this is an act, it's hiding something even worse.
Would Jaskier have sex with her anyway?
No. Jesus. He's flinging himself out of bed at the sight of her. Jaskier may make poor decisions, but the evidence of the past episodes is that he doesn't kink on danger and that's confirmed here, and we've also seen no sign he's invested in fucking the hottest person he can find, which is about the only reason to consider it worth sticking your dick in someone who threatened to cut it off. In order for Jaskier to reconsider Yennefer, he'd need to be in some situation where her bluff is called and he sees she doesn't actually go through with it - and again, she put a knife to his dick. Yennefer is a lot better at bluffing than Geralt was. At this point, either something outside either of their control needs to trap Jaskier in the vicinity of Yennefer and somehow do it at a time when she isn't reacting to being trapped herself by frothing up like a cornered raccoon or Yennefer needs to extend the olive branch (more likely a lot of olive branches) herself.
Jaskier says something that's plausibly a third wish and Yennefer lets him go. Further showing just how scared of her he is, after getting out of the place and seeing Geralt, he says, "Oh, Geralt. Thank the gods. I might live to see another day." - so, he thinks Yennefer will reappear to murder him at any moment.
Geralt: "Jaskier, you're okay."
Jaskier: "I'm glad to hear that you give a monkey's about it."
From Jaskier's point of view, Geralt was warned the mage was dangerous, knew Jaskier was really badly hurt...and then Geralt fucked off and left him to his fate.
Now, I'm pretty sure Jaskier gets the rest of the story after this, so I think he drops the resentment. Unfortunately we can also assume Geralt doesn't get into how far he was willing to go to convince Yennefer to help, so it won't address Jaskier's original issue, about if Geralt truly cares about him. Jaskier can probably fill in some of it, but he's also about to see Geralt charge into a building and almost die to save someone else.
Also, Geralt's response to Jaskier sarcastically saying that and once again showing he's concerned about if Geralt cares is, "Let's not jump to conclusions." so yeah, really not helping Jaskier's underlying fears.
Jaskier then describes Yennefer: "Well, black hair, devilish eyes, was painting an amphora on her abdomen."
I believe this is confirmation that Jaskier is colorblind because he gives the color of her hair, which is ordinary black, and is paying close enough attention to detail to notice exactly what she was painting, but does not think purple eyes are worth bringing up as an identifying feature. The alternative is that purple requires elven genes and Jaskier knows it, in which case he's being an awful, awful person to use "devilish" to mean elven (it also would open up the also awful possibility that the reason he said he definitely hadn't had sex with her wasn't that she doesn't look happy to see him, but that he would never lower himself to have sex with someone of mixed race). But that seems really unlikely given what we've seen is it's possible for Yennefer to keep her ancestry a secret. The evidence points to Jaskier just not having any idea what color her eyes are. By interesting coincidence, any colorblindness that would render Jaskier unable to distinguish between yellow and green would also see purple and blue as the same color. (Protanopia, deuteranopia, or fully black-and-white achromatopsia.)
Geralt: "She wants to be the vessel."
Jaskier: "What, you know this woman? Of course you know this woman."
"this woman" would be the mage they were looking for. Assuming he remembers events up to falling asleep, he'd know Geralt talked to Yennefer about healing him. Either he doesn't remember getting that far or he's just so freaked out from what's happened that he isn't thinking straight. I'm inclined to think he's just too panicked to think at this point, because we know he was paying attention during the initial conversation about them needing to find a mage.
Geralt: "She wants to become more powerful. But she'll die."
Jaskier: "Well, let's pray for her on our way out of town."
That Jaskier isn't thinking straight makes it hard to know quite what to make of this. Jaskier definitely is fine with Yennefer dying and possibly considering that actually desirable, but also, I think as far as he knows she's a serial killer and they're next.
He objects to Geralt heading into danger - "Are you perhaps short of a marble?" and then, "Oh, no, no, no, no, no. Do not tell me that this is finally the moment you've decided to actually care about someone other than yourself?"
This is hugely unfair, not just in the context of the rest of the episode (no matter how confused Jaskier is, he should at least be clear on the fact he was choking to death on his own blood and Geralt got him into town and searched for someone to help) but the context of everything else we've seen between the two of them. It is, however, completely in line with Jaskier feeling like Geralt doesn't care about him, particularly if that's just taken another blow because he thinks Geralt abandoned him while he was near death.
"Leave the very sexy but insane witch to her inevitable demise!"
Jaskier really, really does not like Yennefer. As I said, I would think he ends up getting the full story from Geralt, but while "I insisted on staying by your side in case she tried to pull anything, so I got mind-controlled and then woke up in jail but luckily someone decided to beat the shit out of me before my execution so..." certainly puts Geralt leaving in a better light, it's absolutely not going to improve Jaskier's opinion of her.
"She saved your life, Jaskier. I can't let her die."
I think this confuses the issue of if Geralt cares about Jaskier even more.
Remember, the first time they met, Geralt does everything he can to save Jaskier, including offering his own life up. He also expresses concern and compassion for the people intending to kill them. Here we have a similar situation - Geralt is indicating he values Jaskier's life, but also he's about to risk himself for someone else who Jaskier thinks is some terrifying monster. So, does Geralt care about Jaskier? Did any of that mean anything, or would Geralt have done that for anyone, even someone he hated?
And we know that Jaskier directly says he doesn't understand: "Why did Geralt go in there? It doesn't make any sense. What, to save a mad fucking witch? Why?"
At this point there's not really any good answer for Jaskier - either Geralt died viewing Jaskier as a nuisance, or if he did care and that's why he felt he had to help the mage, then Jaskier managed to get him killed.
"What am I supposed to do now, hm? It wasn't supposed to go this way. I'm gonna write you... the best song... so that everyone remembers who you were, what we did, everything we saw. And I will sing it...for the rest of my days."
This is really sweet. I think it's especially meaningful that he says he wants people to remember Geralt specifically - the we is about the things they did together, but it's only one person he wants to make immortal here, when other times he's talked about his own fame.
"He always said I had the most wonderful singing voice."
Now, this does seem like the general trope of characters misremembering things to put everything in a better light after an apparent death. That said, it's entirely within reason that Geralt has said complimentary things about Jaskier's singing. And it's almost certain Geralt's done something, probably a lot of somethings, Jaskier could reasonably infer was approval. We know from this and the previous episode that Geralt does intentionally act closed-off around Jaskier or pretend he doesn't like things he actually does, so Jaskier's right to think he needs to read between the lines to know how Geralt really feels. The third episode establishes Jaskier has gotten a ton of songs out of Geralt, all of which would have been sung a lot during the creation process, and even if Geralt tried his hardest, he would've reacted at some point. (There's also the fact that good lord Jaskier does not shut up. I think we can infer that, no matter how much of a doormat Geralt may be, if Geralt had any issues with Jaskier's voice he would have snapped by now.)
Finally...
"Oh, they're alive. They're really alive! Whoo!"
Jaskier is not broken up to see Geralt fucking someone. (And it would be not only absurd but awful of him given he was fucking the countess and used his second wish to try to go back to fucking the countess, and also thought it plausible he'd had sex with a stranger when he woke up in her bed.) More interestingly, he doesn't seem particularly concerned Geralt is specifically fucking the "very sexy but insane" "mad fucking witch". Jaskier has previously been very confident that Geralt would be fine no matter the situation, but moments ago he was willing to believe Geralt dead. It's possible discovering Geralt has miraculously survived has put him back in the mindset of Geralt being an unkillable badass. There's also that "Um... Not to be... untoward or anything... but... ...did we... you know... ...do the, uh... Ooh, Go-- Oh, no! No! Definitely did not butter that biscuit." implies that Jaskier assumes anyone you sleep with would certainly be friendly afterward. While he's going to be very negative toward Yennefer next episode, I think Jaskier defaults to sex = everything's fine between us for the foreseeable future at least. (Which would mean Jaskier not only isn't into hatesex personally, but does not understand it exists.)
In conclusion:
Jaskier is having a really bad time of it this episode! He's not just sad about being discarded by the countess, he's upset about what if everyone feels that way about him and is looking for reassurance. That Jaskier is drinking something gross while mentioning he has no food or money for food means Jaskier's been more concerned about drowning his sorrows than taking care of himself. Given all that, while Jaskier does a lot wrong this episode, it's wholly understandable.
Despite how rough things are for Jaskier, we can see he really does care about Geralt - he tries to talk to Geralt about Geralt's own problems as soon as he realizes anything's wrong, he tries to talk Geralt out of risking his life, and he's devastated by Geralt's apparent death. He also shows that, despite the misinterpretations he's made about Geralt's behavior in the other two episodes, he does pay close attention to what's going on with Geralt. If he doesn't understand Geralt, it's not for lack of trying.
But he's really insecure this time. He loses his temper easily, and while he trusts Geralt to save him while Geralt's there, after he wakes up to find Geralt gone, he doesn't question Geralt's apparent abandonment of him. Even Geralt showing up (clearly about to enter the place he just left) and expressing relief he's okay doesn't get Jaskier to change his mind on that because it's based on how Jaskier feels like he's easily discarded.
As rocky as their relationship is here, if we compare it to, say, Yennefer and Istredd's fight, you can see it's still overall a decent one. Jaskier tries to get more from Geralt but things don't spiral out of control when Geralt doesn't react the way he wants, and even the actual fight manages to stay restrained rather than lashing out worse and worse with each exchange. And this is with both of them starting off extremely upset and significantly impaired by alcohol and sleeplessness.
Jaskier wants nothing at all to do with Yennefer. Not only does he have the most upsetting interaction with Yennefer of everyone, but he finds her terrifying even before she does anything. I think it comes down to that Jaskier is really observant and likely picking up on things others miss about Yennefer, but he doesn't have any idea what it all means (just like he can't make sense of so much of Geralt's behavior) so he's getting "looks like a person but doesn't act like a person" and panicking. Combine that with the fact Yennefer is legitimately quite dangerous, and that he can't possibly predict what she'll do next? Yeah, getting out of there and hoping she explodes herself is a smart reaction.
Jaskier seems to have some almost naive expectations about sex where the other person is always happy to see you the next morning, which suggests he must be at least reasonably selective about who he's been having sex with. To go back to the fourth episode for a moment, the people Jaskier gets in trouble for having sex with are "Wives, concubines, mothers sometimes." Notably lacking? Daughters. Jaskier seems to have been sticking with experienced people who know what they want. This may be intentional or it may have just happened because Jaskier gets sex by saying he's available and then going with whoever responds first, which is not a method that gets you a lot of blushing virgins.