Chapter Text
Stiles thought that, in general, his relationship with Derek was pretty healthy. Well, as healthy as it could be when they were as likely to be going after whatever supernatural terror was lurking around Beacon Hills in any given week as going out to a movie or to dinner. They talked about their days, they cared about each other and even Stiles’ dad came around after the whole werewolf reveal.
No, their relationship was fine. It was the sex that was fucked up. Stiles knew that if any of his friends or, god forbid, his father, knew what was going on, they’d be pretty horrified. He wasn’t exactly experienced, but he knew what he was doing was stupid, and maybe even dangerous. Sometimes he was afraid, although he couldn’t have said if he was afraid of what might happen if things went wrong or whether he was afraid this was the only way he could achieve such heights of intensity. He was afraid of a lot, but never of Derek himself. Even though sometimes he wondered why he wasn’t.
The noise of Derek climbing in through his window woke him up. He was still somewhat groggy when Derek took off his clothes and slipped into bed with him. The surface of his skin was cold, having just been exposed to the cool night air, but as always there was a deeper heat radiating out from him.
Stiles couldn't see the expression on Derek's face, but he could feel the strength in his arms when Derek held him closely, desperately.
"What's going on?" he asked.
"Peter and I had a fight," Derek replied.
"Verbal or physical?"
"Both," Derek answered, reluctantly. "He left, I... I don't think he's going to be back, not for a while." He sounded so sad and lost. "I know it's probably a good thing, but as much as I hated him, he was the last link I had to my old life, you know?"
Stiles kissed him, but he could feel the tension in Derek, tension that wasn't going away just from cuddling.
"Derek, what do you need?"
"Stiles," Derek just said his name, sounding thoroughly broken and on the verge of tears. "Stiles, Stiles, Stiles..." he spoke into Stiles' neck. Stiles felt a shiver of apprehension and excitement. They were too closely tied for comfort, he knew that, but how could he deny Derek?
Derek took his silence as acquiescence, which, really, it was, and bit down sharply - with human teeth - on Stiles' neck, where he had just been whispering sweetly. Stiles didn't think he was going to see sweet again for a while. He didn't think Derek had broken the skin, but it was close. The stab of pain rushed through his system, heightening everything.
Stiles usually slept shirtless, so Derek only needed to remove his boxers to get full access to Stiles, which he did with alacrity. Then his hands were everywhere, occupying every inch of his skin, using his supernatural speed (or, so it seemed to Stiles, anyway) to be more than one place at once. He wasn't gentle; he wasn't aiming at pain but he wasn't careful with his movements. Stiles just let him. He knew that he was only a participant in this, not an independent actor - he could tell how it was going to be.
Derek's mouth was leaving bite marks on his body - his chest, his shoulders, even his jaw once, and while none of them were as hard as that first bite, he knew he was going to have to use that concealer he had been so embarrassed to buy last month. But he didn't try to stop him, not when Derek was making pleased noises after every bite and the tension was starting to drain out of him.
Derek's hand moved down to roughly play with Stiles' balls and cock, which was already hard and full, and Stiles felt a little ashamed at how Derek's manhandling could do that to him so quickly every time. He sometimes wondered if Derek thought less of him for it. But tonight he wouldn't find out - Derek either talked filthily the whole way through sex or not at all, and sometimes the worse nights were the silent ones. It was as if Derek was so distressed he couldn't even find words.
But while Derek loved Stiles' cock, he really loved Stiles' ass so Stiles wasn't surprised when Derek's attention moved there. He clenched in reflex as Derek's fingers started tugging at his rim, which did not make Derek very happy. He growled and bit Stiles' shoulder again, pinning him in place.
"I'm sorry, I'm sorry..." Stiles gasped out, feeling the twin pains of Derek's teeth on his skin and his fingers nudging into his hole, unlubricated and insistent. He knew Derek wouldn't stop until Stiles showed him he was sorry, rather than just saying it, so he tried his hardest to breathe through the pain and relax the ring of muscle so Derek could do what he wanted. When Derek felt the lessening of resistance, he grew gentler, licking at the spot where he had actually broken the skin this time and retreating with his hand, back to pulling his ass open at the edges rather than trying to push in. Stiles could feel the beginnings of tears in his eyes and really hoped Derek would go for the lube soon.
It took a few more minutes, but thankfully, he did. Not a lot, but enough for the pain to be mingled in with the sensations suffusing his body rather than to stay sharply located where Derek manipulated his flesh. He had three fingers in Stiles now - not pushing in and out in a directed way, but moving to and fro and around. But Derek couldn't get the angle he wanted by reaching around. Derek kissed him on the mouth, tongues touching, forceful but sweet, in its own way.
Then Stiles was no longer lying on his side, facing Derek, but on his shoulders with his knees underneath him and spread open; a perverted version of child's pose. (He had discovered this when he tried a yoga class a couple of weeks ago - it seemed like a good idea to improve his strength and flexibility given his recent activities, but this was one of Derek's favourite positions for him and he kept getting hard so he had to leave the class in the middle.)
Derek sat behind him and used his hands to spread his cheeks even further open, so that Stiles could feel the air of the room on his exposed and already somewhat sore hole. Derek just kept him there like that, open, waiting, for a while - for too long, because Stiles couldn't help it when he eventually twitched and clenched again. He winced immediately, even before Derek did anything, and the tension just made it worse when Derek put both of his thumbs in Stiles and wrenched him as wide open as he could without actually tearing Stiles.
Stiles cried out and probably just plain cried, too, words of contrition and obeisance tumbling out of his mouth, but Derek just held him there and it was Stiles and not Derek who eventually relented, Stiles' body which gave in and made the stretch bearable.
Derek opened him more and more with his fingers, going wider just a bit before Stiles adjusted to the last width, keeping him on the edge both of unbearable pain and orgasm. Because yes, his dick was dripping with precome under him, despite - or rather, because of - Derek's actions on his body. He knew something was wrong with this and his tears were as much of shame as of pain. But Derek didn't notice or didn't care.
Stiles couldn't see what was happening, as his head was down on the bed, but he wasn't surprised to feel something different at his entrance - Derek's cock, actually fairly lubed up. And Stiles knew what that extra lube meant and tried to move away, but Derek was faster than him and held his hips in place as he pushed all the way in in one jab. And he felt the swelling at the base of Derek's cock growing.
This was something Scott hadn't told Stiles about. Actually, Stiles wasn't even sure that Scott knew about it - he wasn't sure if it was an alpha thing or just a control thing, because Derek seemed to be able to control his knot pretty well - it was present or not as he wanted it, and its size also seemed dependent on what Derek wanted. Or maybe it was just bigger some times than others and Derek acted accordingly, Stiles wasn't sure. They hadn't talked about it. But he knew that when Derek was in a mood like this and used a lot of lube, the knot was going to get big.
And it did. Quickly. Derek only pulled out and went all the way back in a couple of times before the knot stopped being able to pass his rim without excruciating pain, so Derek just stayed inside, pushing forward rhythmically but not pulling out. Stiles still felt like he was being split open, like his body would part like a nut with its shell cracked and all that he was inside would be visible and vulnerable. Only Derek's hands on his hips, rubbing soothing circles into his skin, were holding him together, as Derek's dick took him apart.
It wasn't long before he came without Derek even touching his cock.
But Derek didn't stop.
He just kept pushing and pushing until Stiles was hard again then pulled back enough for Stiles to feel the pressure of his enormous knot at his rim. He thought he must have screamed when one of Derek's hands moved to cover his mouth and the other started jerking him off, hard. When he started to come for a second time, Derek actually pulled all the way out and pushed all the way back in and Stiles couldn't understand how that much pleasure could coexist with that much pain - he thought at first he must be actually ripped open but as the pain receded he figured he must still be whole.
Then Derek's knot started pulsing in him as Derek came with a groan, and if Stiles couldn't actually feel his come shooting into him, he imagined the warmth coating him inside, healing his hurts. Derek slowed but didn't stop his thrusts and his knot stayed in place, and Stiles knew this was still far from over.
Derek rolled them onto their sides so he could stay inside Stiles but have better access to his cock. At first Derek's touches were pleasant, fondling his balls and rolling them back and forth, gently stroking his cock up and down. But then they grew directed, stripping him up and down so that he started to chafe despite all the come, but Derek's knot was still pressed against his prostate and his warmth was all around him and after what felt like ages, he whined as he came for a third time.
But if he let himself think it was over, he was wrong. Derek started the whole thing again, still not saying a word, and he moved inexorably as Stiles started to beg for him to stop.
"No, oh god, Derek, stop, I can't, please, please just stop..." the words sounded like a repeating chorus.
"Shhh," Derek broke his silence to make comforting shushing noises in his ear as he continued, and Stiles was sobbing as he came a fourth and a fifth time.
After the fifth time he just wasn't getting hard again, no matter how much longer Derek tried. His knot was receding and Stiles' body was just done, teenage recovery time be damned. When Derek slipped out of him, a rush of come following after, Stiles felt an overwhelming relief but also loss.
The relief didn't last long as Derek moved down his body before he could turn around, pushing Stiles onto his back and mouthing at Stiles' red, abused, limp cock. He felt too tired even to object or cry anymore, all of the sensation, both pain and pleasure, wrung out of him. But Derek kept going, sucking him into his mouth, licking around the head, clearly not minding that there was no hint of life or hardness in him any more. Derek's fingers moved back to his hole which was still so, so sore and Stiles wanted to clench or cry when he felt Derek's thumbs pulling him open again, but he didn't. Derek hummed approvingly around his pathetic cock, still soft and warm in Derek's mouth, and he kept going for god knows how long - Stiles wasn't sure, he had lost all ability to judge time and he might even have fallen asleep for a while, pried open and dripping under Derek's eyes.
Finally, finally, Derek climbed back up the bed to take Stiles in his arms, to curl around him, a protective layer against the rest of the world. Stiles held Derek's face in his hands and licked the tears off Derek's cheeks, as plentiful as his own, before falling asleep happy.