Various X Reader Lemons

Underfell Sans x Reader: Dangerous

You hadn't been in the Fallen Underground long, but you'd already made friends with Sans and Papyrus. Today, Sans had invited you over, but when you opened the door, someone toughly yanked you inside and pinned you to the wall inside the darkened house.
"Wh--?"
"Human... My brother is looking to drag you into the bonezone. He has done this with every female human that has fallen here, and none of them... Well.. They were torn apart by his bare hands."
You shivered; but you couldn't decide if that was a bad thing.
Papyrus sighed, and let you go.
"I warned you, human. If Sans tries to get you into his room, by persuasion or force, run."
And with that, he walked out of the house and slammed the door. "Sans?" You called. "Where are you?" Walking around, you wondered what Papyrus could've possibly meant by the 'bonezone'. (That's right, you're a cinnamon roll) You walked upstairs and were about to knock on Sans's door, when he yanked it open, a sly smile on his face.
"Hey, (y

)." He purred. Your cheeks started turning pink, but luckily it was dark; he probably couldn't see your face. "Why don't you come in? I wanna... Talk to yo about something."
Confused, you walked in and sat on his bed. He closed the door behind him and locked it swiftly. A red glow from his computer washed over the room as you started to speak.
"Hey Sans, what's the bonezone?" He stiffened and whirled around to meet your gaze, grinning evilly.
"I thought you'd never ask. Here, let me show you!"
(Well. 0 to 100 real fast.)
With that, he pounced onto the bed, knocking you flat onto your back. His eyes glowed dangerously bright as his teeth grazed your shoulder.
"S-Sans!" You whimpered as he ran his tounge over your collarbone. Ferociously, he ripped your shirt apart and clawed your stomach with his fingers, leaving reddish trails in your skin.
"We're just getting started, hun~" he growled, and grabbed the seam of your pants, ripping them off with your underwear. You tried to cover your sensitive parts with your hands, but he used your soul to pin your hands above your head. He ripped off his jacket and shirt, showing that he wasn't wearing anything at all. You crossed your legs tightly, but he forced them open with his hands, pulling them apart as far as they could go. You were a screaming mess, but he gagged you. "(Y/n), honey, my room is soundproof!" He laughed maniacally as his hands trailed slowly up your legs, and he ran his fingers in slow, pressured circles along your clit. You whimpered as he gently lifted your folds, saliva pooling in the corners of his mouth. "You ever done this before?" He purred quietly. You were pinned down so much that you couldn't move your legs, arms, or feet, but you shook your head in a slow 'no'. His teeth grew sharper noticeably, and his tounge hung out of his mouth, dripping wet. "Then.. Let's get you ready." He slowly stuck one finger inside of you, going slowly and keeping it as straight as he could. When he got so far as he couldn't go any deeper, he stopped. Then he held his hand against your body with his other and jerked his finger to the side. You arched your back and moaned; this felt amazing. He slowly rotated his finger inside you, and you twisted your legs to try to get more friction. He got the idea, and went extremely fast, inhuman speed as you groaned under him. Two fingers, even three fingers until you jerked and released all over his hands. Emabarassed, you looked away as he slowly dragged his fingers out and stuck them in his moured.. "Mmm.. kiddo, you yase pretty good... For a human." He leaned over you and took the gag in his teeth. "(y

)..? Do you wanna have a good time~?" He summoned a glowing red dick, and pressed his pelvis up against yours. "Can I~? Oh wait, I don't need your prrmission~!" He growled seductively, and forced his member inside you. You screamed, and moaned loudly as he moved, cursing and sweating. You released all over his member as he summed. He slowly drew out, and got dressed in a flash of red. "Well, kiddo, that was great. We gotta do that again sometime." Then he let you sit up, shaking from all of the pleasure flooding your body.

"But.. Sans... What's an orgasm?"