If you don't like bottom!Derek, just skip this chapter but if him being submissive is the issue, I wouldn't exactly say that's how it goes. Either way it's basically just smut in this chapter, so if you skip it, you aren't missing anything out of the storyline of any importance.

Derek whined low down in his throat when Stiles finally moved, when he reached up and curled his fingers into Derek's hair again, pulling him closer and smoothing along his heated cheeks with his thumbs like he could wipe away the blush that lingered there. He pressed a kiss to Derek's mouth, pressing his tongue against the seam of Derek's lips and knowing that the other Alpha could feel his nod.

And after that, it was like a fire was burning underneath Derek's skin with the way he moved. His actions were fast, jerky almost, as though he thought that Stiles was going to change his mind if he didn't move quickly enough. Derek's weight lifted off of him just long enough for him to reach into the bedside cabinet and then he was back, pressing a small bottle into Stiles' hand at the same time as his fingers tugged at the bottom of Stiles' hair as he reeled him in for another bruising kiss.

It was nothing but heat. The feel of Derek above him, the fingers of one hand curling around both of Stiles' wrists and pinning them above his head. The feeling of being pinned down underneath nothing but hard, warm muscle was indescribable. Stiles wouldn't lie and say that he had been celibate in the past years, because honestly he'd been far from it; but nothing had ever come close to the feeling of being with Derek. Sex with someone else was outmatched by just one of Derek's kisses, the pure need that filled the way that Derek clutched at him, the promises that were voiced with each swipe of his tongue.

Stiles was good at finding words for things, but not when it came to this. Not when it came to Derek. He didn't know how to explain that feeling that built in his chest when Derek straightened up above him, his thighs either side of Stiles' hips as he straddled him. It made him fell like a teenager again. Just the heat in Derek's gaze when he stared down at him. Stiles was used to people looking at him with lust in their expressions, but whereas normally he would have preened under the stare, the weight of Derek's gaze made him want to squirm. It made him feel like he was itching underneath his skin, like if he didn't move, if he didn't make Derek do something fucking now then he was going to go insane.

In the past, sex had always been about him being the one in charge. Even whilst being the bottom, he was still the one calling the shots. But right then, like always, he was getting off on Derek's dominance. Even knowing that he was about to be the one doing the fucking, even being able to picture that blush on Derek's cheeks and the nervousness in his expression when Stiles closed his eyes, there was still no way that this situation was at all painting Derek to be the submissive one.

Just the way that he was pinning Stiles to the mattress was so completely Derek, it was so in character and so normal that Stiles could feel himself growing hard again. His recovery time shorter than it had been since adolescence. But then maybe that was the thing, even his body couldn't help but react just as it would had he still been sixteen when it was faced with Derek. He couldn't help it. He didn't want it to change.

"Just this once. Just now," Derek growled in between biting kisses across Stiles' collarbone and neck, red blooming against his creamy skin only to fade almost immediately, "Just this time. Just the first time. Want to smell like you, want you to make me smell like your Pack, want to be yours."

And fuck he hadn't thought about the reasons why Derek would want this. But of course, of course it had to do with scent. He could only imagine what Derek would smell like after they did this. There was always something different in the scent that lingered on someone's skin after they'd been fucked. It was different from when you were the one who was doing the fucking. It went deeper, was more primal almost, more possessive.

And oh my God Stiles couldn't stop moving, couldn't stop squirming at the thought of Derek smelling like him, of smelling like his after this. It felt like every single nerve ending in his body was on fire and he knew that was all the wolf. He knew that this had nothing to do with the human part of him. The physical reaction he was having to his thoughts stemmed straight from his wolf's possessiveness, from its cries of mate.

"After this I'm going to make you mine," Derek growled right in his ear, sucking on the skin underneath it, seeming desperate to try and make a mark stick and Stiles almost wished he could turn his healing off to make that happen. He wanted to be marked as Derek's, he wanted to show the world, to show the entire Pack. "Going to fucking knot you, going to fill you up and make you scream."

Stiles shivered and moaned, choking on air as Derek straightened up, the click of the cap of a bottle being opened and then he was watching Derek fuck himself on his own fingers. He was watching his back arch and his hips grind down against Stiles' as he worked himself open. And Stiles wanted to see, he wanted to push Derek off of him so that he could see, so that he could watch Derek open himself up properly, join in even. Except he couldn't tear his eyes away from Derek's face. He couldn't stop staring at his expression, at the blissed out look, at the way the blue of his eyes was almost completely swallowed up by the red.

The colour was practically pulsating and Stiles licked his lips at the sight of Derek's fangs poking out of his mouth. He lurched upwards, grabbing Derek by the back of the neck and crushing their mouths together. Derek made a sound of surprise, his fangs cutting someone's mouth with the sheer brutality and recklessness of the kiss, but Stiles had no clue who it was that was bleeding. They healed too quick for them to even really feel it, but the taste was still there, bursting into life on Stiles' taste buds and making him moan even though he was all too aware of how fucked up that probably was.

Derek's had let go of his wrists at some point, but he couldn't remember when. He only became aware of it when Derek's hands on his shoulders pressed him back down into the mattress again and he would have protested, would have strained against the action if Derek hadn't been bending down with him. And honestly, he couldn't think much past the low, needy sound Derek made when he pulled his fingers out of himself, could hardly even register the slick feeling of Derek smearing lube on his chest.

Then he was choking. Then he forgot how to breathe.

Then all he could think was: fuck. Tight. Hot. Derek. Fuck. Derek. Fuck. Too tight. Fuck. And it seemed like his sole purpose in life was making sure he didn't end this whole this before it had really ever begun. There was no way of describing how it felt to have Derek pressing down onto him, to have Derek squeezing his dick with nothing but slick, barely tolerable, fucking amazing heat.

He finally managed to drag in a breath when he bottomed out and he would have loved to say that he contributed somehow to the experience, but really he didn't do much other than lie there. He couldn't do much other than lie there, concentrating hard on not coming as Derek rose up and down on his cock.

The movements of Derek's hips were lazy almost, but Stiles knew that if he sped up at all then Stiles was a gonner. It was all over if Derek so much as squeezed his muscles and he tried to convey that somehow through curling his fingers around Derek's thighs, digging human nails into his flesh. He didn't know what he was supposed to think of the wicked grin he got in return.

There was something incredibly open about the expression on Derek's face. It was blissful, happy even and Stiles hadn't seen anything more beautiful in his entire life. That expression was enough to make him forget that Derek had ever frowned once in his life. It was secret and private and just for him and Stiles bared his teeth and snarled at the thought of anyone else getting to see Derek like this.

Derek made a stuttered, choking noise when Stiles wrapped his fingers around his cock, jerking it just twice and twisting ever so slightly on the upstroke. And that was all it took to make Derek come. Honestly, he didn't know why he'd thought Derek would be any better at coping with the sensations than he was. He didn't know why he thought Derek wouldn't be right there at that edge with him. It was the feeling of Derek's internal muscles spasming around his cock that had him plunging down over that ledge.

It was like their roles had been reversed, because whereas Stiles' release was silent, his head tipped back and his mouth open like he was screaming, Derek's howl was thunderous and almost triumphant. He dug his nails into Stiles' abs and to his credit, Stiles didn't so much as flinch when they punctured his skin, the claws pushing through past human nails.

Derek pitched face down on the bed next to Stiles, his face pressed into the pillows and Stiles seriously suspected that right then he was feeling like his entire body was one huge elastic band. Stiles knew the feeling and he knew just from the way that Derek was sprawled that nothing was going to move him for a while.

Stiles rolled over and nestled into Derek's side, flicking his tongue out to taste the sheen of sweat that clung to Derek's skin at the base of his neck. "Just so you know, I'm expecting that knot when you wake up big guy," he said, tapping Derek's ass for emphasis and laughing when Derek did nothing more than huff and throw an arm around his waist, pulling him in closer to his side.

He smiled against Derek's shoulder. "Funny how you always said I was a pain in the ass," he muttered, "Didn't know you wanted to take that quite so literally, Sourwolf." He told himself that the only reason Derek didn't ordain to reply to that one was because he was asleep.