Notes: I wrote this as a birthday present for my best friend because I love her. I don't actually even ship Steter, but here it is.

It was wrong. So wrong. Wrong, wrong, wrong.

Oh god, but so fucking good.

No Stiles, he reprimanded himself. This is not good, this is bad, this is so bad, this is-

"Oh fuuuuuck," he swore, his words turning to a low moan when Peter hit just the right spot. The spot. The one that made him keen with pleasure, panting and swearing, skin slick with sweat.

Peter growled, a sound not quite human, slamming himself back in to hit it again and again and again.

And Stiles was whining and begging for it. "Oh god, please, shit, so good, don't you dare -ah- fucking stop."

This should not be happening. He knew it shouldn't be. Everything about this was 100% not a thing that should be happening even a little bit. Peter had killed people. He'd manipulated Lydia after he'd almost killed her too. He was the reason they'd gotten involved in this supernatural mess at all. He was a bad guy.

A bad guy who knew how to use his-

"Ah, oh fuck!"

Stiles came hard, come splattering his stomach and the couch he was currently bent over, tremors racking his body as he went limp, sated.

Peter came a moment after, pushing himself back in with a grunt before he stilled, fingers gripping the younger boys hips tight.

Stiles was a mess -sweaty, mussed hair, and a bruise he could practically feel blooming on his right thigh. His body felt heavy with pleasure and his brain a little fuzzy as Peter pulled out, leaving him empty.

He almost felt content, laying half over the couch like that, boneless. But even though his body had betrayed him -again- he knew this was not how things were supposed to be.

"I hate you," he said, pulling his jeans back on and looking around for where his shirt had gotten off to.

Peter just smirked at him, lounging naked on the couch they had just violated, like he hadn't a care in the world.

"Sure you do Stiles."