Meanwhile, Castiel is in full gay panic mode.
Unlike Dean, Castiel's known he was gay pretty much since the beginning of time, and he isn't going to waste time pretending he doesn't know. As an actor, he has no problem acting like a Straight Man™. He blends right in with the rest of the Straight Men™ of Hollywood when he refuses to even mention the LGBT+ community. Of course, he's just wary of accidentally outing himself or being outed, which Straight Men™ don't have to worry about, but the backlash they get for their silence is the same.
None of his PR stunt relationships have ever meant anything to him. He's never had any "friends with benefits" like he knows some celebrities do. He just pretends to be in love when the cameras are watching, and drops the act behind closed doors. His fake relationships have never gotten very serious, and they only last a couple months at most, so he doesn't have to work very hard at it.
But no matter how easy it is to keep the Straight Man™ facade up when he's faced with women, he's beginning to think he'll always struggle when he's faced with hot guys.
He had been watching Dean Winchester warily all night, which, he must admit, was rather pleasing on the eyes, even if it was stressful everywhere else. A Fake Straight Man™ obviously can't hit on a real Straight Man™, but that didn't mean Castiel couldn't talk to him, right? Straight Man™ to Straight Man™? There was no reason Dean had to know that Castiel was actually as straight as a circle.
But it's a lot harder to pretend to be straight when there's a hot guy with his arms around you. Dean was just trying to teach him guitar, and logically, he knows that. That didn't make his closeted ass any less uncomfortable. Except he really wasn't uncomfortable as much as...
Oh, god.
He has a crush on a straight guy.
It's not even just that, though. He has a crush on the straight guy who's currently "dating" his future pseudo-girlfriend. Not only is Dean off limits in a romantic-slash-sexual sense, but he's off limits as a friend, too.
That's probably for the best, though. He's kind of an awkward guy, and it only gets worse when he's uncomfortable. Being near someone he likes is definitely going to bring the awkward out. He should just stay away from the guy as much as he can. It's going to be disappointing, not getting to see his face again — he has a very attractive face — but hey, that's what Google is for, right?