The first time it happened, Stiles hadn’t even realized how strange it was until after he’d left and was walking home with his hair dishevelled and a sock missing. He remembered how he’d ended up in Derek’s bed, and why they had ended up fucking like there was no tomorrow, but he hadn’t realized he’d be walking home wondering how it had happened.
The night before, he’d had another dream about the Nogitsune taking over, and killing his dad. It had made it impossible for him to sleep, so he’d gone out for a walk to clear his head. He hadn’t been planning on walking far, just a few blocks and back, but he’d ended up out near the woods at the same time Derek had been stepping out from patrolling the area.
They’d chatted for a while, Stiles explaining what he was doing out so late, and Derek had insisted they go to the loft so he could drive him home. Once they’d gotten there, Derek had gotten him a drink while he used the restroom and suddenly they were sitting on the couch talking about all the shit they’d been through and how the world was a terrible place.
Stiles didn’t often let his nightmares get the best of him, but more often than not he felt like the world was going to shit and they were all going to die. And he wouldn’t even die getting laid on a regular basis.
Somehow, that had ended up with Derek telling him he didn’t get laid much, either, because every time he found someone to fuck, it ended up turning everything to shit. He’d fucked Kate, and she’d murdered his family. He’d fucked Jennifer, and she’d been a homicidal psychopath. He’d fucked Braeden, and slowly turned human.
Granted the last one hadn’t been Braeden’s fault, but that was what Derek associated her with. His stint as a human.
When Derek had said he’d like to fuck someone without anything going wrong, Stiles had replied with, “Why don’t you just fuck me, then?”
And that was how they’d ended up naked and fucking in Derek’s bed, with Stiles’ legs thrown over Derek’s shoulders, his head thrown back, and moaning. They didn’t kiss, because somehow that made it too intimate, and that wasn’t what this was about. They hadn’t wanted anything more than a quick release, a moment to just feel something before having to return to their regularly scheduled lives.
When they’d finished, Stiles had said he should go, but Derek insisted it was stupid of him to leave and that it wouldn’t be the first time he spent the night, which was true, so he passed out naked beside Derek.
The next morning when he’d woken up, Derek was still sleeping and Stiles was late for work, so he’d pulled his clothes on, gave up looking for his missing sock, and had left the loft without a word. He’d made it to work two hours later, smelling like sex and looking debauched, but his boss didn’t say anything and Stiles just did his job.
He didn’t see Derek for days after that, because nothing Supernatural had come out of the woodworks to murder them all, so he went about his days as normal and ignored what they’d done.
The second time it happened, Stiles had been sleeping when Derek slid into his room. His dad was at work, so he could’ve rung the doorbell, but Stiles hadn’t mentioned that. Derek had sat on the end of his bed and insisted that he would never be able to stop blaming himself for murdering his family, and that some days were worse than others.
Stiles couldn’t relate, not entirely, but he understood the guilt of something like that given Allison was dead because of him, and somehow they had ended up with Stiles’ face buried in his own pillow and Derek’s dick buried in his ass. With his dad gone, neither of them had to worry about being loud, and Derek even wolfed out halfway through, something he admitted when they were done that he’d never done with anyone else before.
When Stiles woke up the following morning, it was Derek’s turn to be gone, and he had to wash his sheets and blankets before his dad got home. Not that his dad would care he was having sex, he’d just made it explicitly clear while Stiles and Malia had been dating that, “Not under my roof, Stiles.”
It was still his roof when he wasn’t home.
The third time it happened, they’d just defeated the big bad of the week—Stiles was starting to feel like he was in a TV show, with the way something new came up every fucking week—and Stiles was hurting bad. He was pretty sure his shoulder was dislocated, and Derek brought him back to the loft in the Camaro to get him checked out before he went home and worried his dad.
Derek had popped his shoulder back into place, Stiles screaming around the pillow in his mouth, and they’d sat on the couch together while he struggled to get the pain he was in under control.
Derek was covered in blood from various healed injuries and Stiles had dirt and mud everywhere and a few scrapes along his arms and face. A typical day in the life of Stiles and Derek, but still not the life Stiles envisioned himself having back when he was young and innocent.
So, when he was about seven, really, since he had long ago stopped being innocent. Not with the shit he got into as a child.
They’d talked for a few minutes while cleaning themselves up, and when Stiles stripped in the bathroom so he could wash the dirt off his skin, Derek had ended up joining him in the shower and fucking his brains out against the cold tile, water beating down on them and mostly only hitting Stiles’ face over Derek’s shoulder.
It continued on like that for a lot longer than Stiles had realized. One of them would have a bad day, or would need some form of release, and they would either call or show up at the other’s place and they would fuck.
All in all, it worked well for both of them. They got laid regularly, and both of their fears were mostly alleviated. Derek didn’t need to worry about Stiles being bad, and Stiles knew that if he ever got possessed again Derek would be able to defend himself.
They hadn’t ever spoken about rules, but they seemed pretty clear-cut and black and white.
No kissing, no talking about it, no feelings. Just fucking, and the occasional discussion before and after, and that was it.
Stiles knew the unspoken rules, and Derek knew the unspoken rules.
And yet somehow, they’d both broken them at almost the same time.
Stiles’ legs were wrapped around Derek’s waist, his back arched and hands above his head, gripping the top of the wooden headboard while the other drove into him over and over again. Derek almost seemed rougher on days where they’d just finished fighting off some monster, and it left Stiles wishing they fought monsters more often, which was a stupid thing to wish since they fought them plenty often.
Derek’s face was buried in Stiles’ neck, and he was snarling and rubbing his furry face against the sensitive skin of his throat. He’d been in his Beta form almost the second they walked through the door, and Stiles had momentarily been worried for his asshole because claws definitely shouldn’t be going into his body. Thankfully Derek had gone to calm down somewhere while Stiles prepped himself, but damn had he been impatient as fuck by the time he got back into the room.
It was a different dynamic than normal, and there was almost a desperation there when Derek had grabbed him around the waist, yanked him closer, and pushed into him. He’d started up a brutal pace from the beginning, and Stiles was pretty sure what he felt sliding down his sides was actually blood as opposed to sweat, because his sides hurt and Derek’s claws were out so, logically, it made sense to think that he had claws digging into the skin of his sides.
He would’ve assumed that Derek was desperately trying to reassure himself Stiles was okay, considering he’d almost died earlier, but that would’ve implied Derek actually cared about him so Stiles knew it wasn’t that.
Maybe he just realized that his fuck buddy was a fragile human and he needed to get as much out of him as he could while he could. It was hard to really know with Derek sometimes.
Stiles arched his back even more than he thought possible when he came, no stimulation other than their bodies moving against each other. Derek let out one of the loudest snarls Stiles had ever heard before slamming into him hard and stilling, his entire frame tense while he came. He was breathing so hard against his neck that Stiles was actually worried Derek had lost himself inside his own mind and the animal was taking over and his throat was about to be ripped out.
Thankfully, Derek slowly began to relax after a good two minutes, falling on top of Stiles bonelessly and smearing Stiles’ cum along both their stomachs. His softening cock was still buried inside Stiles, but he didn’t mind, this had been happening more frequently of late. Stiles just figured Derek was too lazy to pull out, and since it didn’t bother him, he never thought to mention it.
Stiles let one hand rub smoothly up and down Derek’s sweaty back, the other buried in his hair and scratching at his scalp. He closed his eyes, exhaling softly, Derek’s hot breath ghosting along his neck. It was funny when he thought about how they’d found themselves here. Stiles had had a nightmare, and now they had sex so often Scott was starting to complain.
Scott had never asked about it, but Stiles figured he knew it was just a friends with benefits thing. Hell, if someone else had asked him first, Stiles would’ve been on board either way. The only reason Derek was his exclusive fuck buddy now was because he’d been the first to ask.
Now it was just weird when someone else did. Like Malia, who’d called him a month ago to ask for a casual fuck to release some tension. It had been an awkward call given he’d been lying on his stomach with Derek still inside him and lightly dozing.
She’d admitted she hadn’t known it was a deal exclusive to Derek when he’d told her he was already busy, and while neither of them had commented on it after he hung up, it was something Stiles had realized he hadn’t known they were doing, either. Derek went out a lot, but never fucked anyone, and Stiles had gotten various offers since starting up with Derek and had turned them all down.
“Hey Derek?” Stiles asked. He received a grunt in response. “How come you don’t fuck anyone but me?”
“Do you want me to fuck other people?” Derek asked.
“I was just asking a question.”
“I like fucking you.”
“Okay.” They were silent for a while longer, then Stiles said, “How come you haven’t asked why I don’t fuck other people?”
Slowly, Derek lifted his head to give him a weird look. He looked stunning then, hair sticking up, eyes glassy, cheeks still flushed. Stiles couldn’t stop the laugh that made its way up his throat and, without thinking, he leaned forward and kissed Derek.
It was a chaste kiss, really. Just a light press of lips against his, but he knew the second he’d done it that he shouldn’t have, because Derek tensed and stared at him.
Stiles opened his mouth, closed it, and felt like he had just made a colossal mistake. Everything they’d been doing, all the sex and the conversations and the comfort...
He’d just screwed everything up.
“I broke a rule,” he whispered, feeling dread pooling in his stomach. “Derek, I’m sorry, I didn’t—it was just—”
Derek’s lips were back on his before he could finish his thought, rough hands coming up to cup Stiles’ face and his stubble scratching at Stiles’ skin. It took a few seconds for Stiles’ brain to catch up with what was happening.
Derek was kissing him. Stiles had kissed him first, but Derek was now kissing him back. Suddenly, Derek’s desperation upon their return to the loft made sense, because what Stiles had dismissed earlier was actually exactly why he’d been so desperate.
Stiles had almost died, and Derek had freaked and needed to make sure he hadn’t.
Slowly, Derek broke the kiss, Stiles’ bottom lip trapped between his teeth before he released it entirely, staring down at Stiles.
“I broke a rule, too,” Derek whispered, hands still cupping his face.
“Oh,” Stiles said breathlessly. “I don’t mind.”
Derek kissed him again, and Stiles wrapped his arms around his neck. They would definitely need to talk about this once they calmed down, but for right now, Stiles wanted to make up for all the kissing they could’ve been doing and hadn’t been, so he just rolled his hips upwards and kissed Derek until he couldn’t breathe.
Somehow, death by kissing didn’t seem like such a bad way to go.