Stiles knew he should have been nervous, but he was too amused at how scared Derek had looked. He never thought he'd see Derek look like that, so vulnerable. All it had taken was Stiles' father asking to have a talk with him, man to man, alone. He'd looked at Stiles when he'd said that,alone, meaning get out of here Stiles and let me remind your boyfriend that I own a gun.

It had all been Scott's fault, of course. Stiles had considered hiding his and Derek's relationship from him but he couldn't have if he'd tried. Scott was really getting the hang of his senses now and he'd caught the scent straight away. That and he'd sort of walked in on them. Scott could be dumb when his mind was only on Allison, but he wasn't that stupid.

So Scott knew and that was fine. It was Scott. He told Scott everything anyway. Stiles definitely didn't want his dad to know, though. Not yet, definitely not until he was sure of what was happening. Not until he was sure his dad wouldn't kill Derek. Not that Scott had thought about all of that before he'd opened his mouth. Before he'd asked Stiles if he was going to be sleeping at Derek's right in front of his father and the look on his face told him that he couldn't talk his way out of that one.

That was how Stiles had ended up bringing Derek home to meet his father. The colour had gone out of Derek's face when he'd asked to speak to him alone and, to Stiles, that was just hilarious. He knew that there was no point arguing, so he'd done as he was asked. He'd reached into the back pocket of Derek's jeans, pulled out his car keys and walked out of the door.

He left his front door open a little, just a crack. He had no idea how good Derek's sense of hearing was.

Derek tried not to show how nervous he was. Stiles' father was no wolf but that didn't mean he wouldn't be able to tell. Meeting the parents, that was never good. Fathers didn't like him around their daughters, they didn't like his attitude, his car, the way their daughters hung off of his arm, anything. Stiles was no girl but his father was still protective. Man to man talks, they were code for warnings.

He listened to Stiles' footsteps out to his car, heard him get in. He didn't hear the door shut.

"So, Derek. I hear you're dating my son."

It was a statement and it always started like that. What was he supposed to say?

"Er, yes. I am."

"I do have that right? You are dating? It isn't anything... more casual?"

"No, it's more than casual. We're... dating."

Derek realised that he hadn't said that yet. He hadn't even said it to Stiles yet, but he guessed they were dating. They weren't just having sex. Well they hadn't actually had sex yet. That wasn't all he was interested in, though. He hadn't seen it coming, he hadn't expected to feel anything but irritation towards Stiles but, somehow, in between all of the danger and teaching Scott and just making sure that everyone was safe from the Argents, it had happened. He'd found himself caring about whether or not Stiles got home safe, how his day had gone, just what he was thinking when he just stared, open mouthed... and he needed to stop thinking about Stiles' mouth when he was talking to his overprotective father.

"What exactly are you intentions with him?"

It was a typical question. It was impossible to answer correctly.

"I like your car, you know. Comfy seats."

Stiles was talking to him from outside. He could hear him clearly and he wondered how that was supposed to help him. He would have tried to block it out but he couldn't do that with Stiles. It was like his senses focused in on him. He could smell him all around town, could hear him clearly from further away than normal. He'd thought at first that it had only started recently, since they'd started this whole thing but no, it had always been that way. He'd never been able to shut him out and maybe that was why Derek had found him so annoying at first. Before he'd gotten used to him, before he'd realised that he liked everything that had previously irritated him.

"Obviously I'm never going to be able to look at it the same again. Not after what we did in here last night," Stiles said. Derek clenched his jaw.

"Derek?" his father asked.

"I don't know what to say," he said honestly.

"I mean, I enjoyed myself. I assume you did, you seemed to. I don't think I need your heightened senses to see that," Stiles said. "I particularly liked it when you dropped the seat and climbed over onto me. That was good. I like you on top. Of me, I mean."

Derek could feel his pulse rising. Last night had been perfect. He could smell Stiles all over his car and he never wanted that to fade. He was torn between wanting to go outside to shut him up and wanting to just repeat the actions of the night before. All he knew was he wanted to get out of the house.

"I want you to tell me what exactly you're planning with my son."

"I'm not planning anything," Derek said with a smile, trying to break the tension. It didn't work, but he hadn't expected it to. "I like him, he likes me, I'm going to see where it goes."

"I hope my dad doesn't keep you too long. I'd like to feel you on top of me again. Maybe we could do something in here again, or anywhere really. Anywhere you want to take me."

Derek blinked. He could feel the blood pulsing through his veins. It was cheesy, it shouldn't have made him want to run out to his car and rip Stiles' clothes off.

"I don't mean take me take me. Like take me where you want to go. Unless you want to. You can if you like. We can go somewhere and you can fuck me anyway you want to."

Okay, that was crossing the line. They hadn't even... they hadn't gotten close to that, he'd wanted to, god he'd wanted to look at every inch of his skin, kiss him, taste him, watch him come undone under him but they'd sort of been taking it slow.

"Well I don't think I have to tell you that if you hurt him, it'll be the last thing you do," his father said and Derek gritted his teeth.

Did he know what his son was capable of, what he was saying? No, no Derek was thankful that he couldn't hear him, that he had no idea of what was going through his head. He nodded, as sincerely as he could.

"Okay then, well I think he's probably waiting in the car, so you'd better go. I mean it though. You hurt him -"

"That's not something you have to worry about," Derek said.

Stiles couldn't help grinning when Derek finally walked out of his front door. The smile faltered a little as he got closer and he saw the look on his face, not sure if it was disbelief, anger, frustration. He thought it looked like he was about to tear him apart but he couldn't be sure whether or not it was in a good way or a bad way.

"What the hell was that?" Derek asked as he got into the car.

"What? I was just sitting here, talking to myself."

"Did you mean it?" he asked.

"Mean what? What?"

"The last thing you said. The... suggestion. Did you mean it?"

Stiles felt his face flush, it was a little less easy now that Derek was here with him. He could feel his eyes burning into him and he just wanted to be able to say everything he was thinking. Sure, teasing him when he was in there, talking to his father, that was funny but it hadn't really been about that. When he'd just been in the car, alone, it had felt like he was talking to himself. It had been easier to say what he wanted, what he needed. He knew Derek was taking it slow for him, not wanting to push him too far, too soon but, fuck, Stiles didn't want him to wait for him.

"Yeah, yeah I really did," he said.

"Okay. Good."

Derek reached over a took the keys from his hands, slipping them into the ignition. The car roared to life and Stiles wanted to ask where they were going but he couldn't get the words out. The sun was setting and the light was turning to a deep red hue over the town. Derek looked around at him, eyebrows raised and then he realised that he'd been staring. He'd been staring at the way the light danced off his face as he drove and now he was too aware of the way his mouth was hanging open.

They took a few familiar turns and then he knew where they were going. Stiles grinned and slid his hand into Derek's lap, running his fingers along his thighs. Derek didn't look at him but there was a low growl, a warning. He always complained when he started things in the car. Even the night before, he'd told him to stop, told him that he needed to concentrate on driving before he'd swung the car around and parked it somewhere nobody would see them.

Stiles ignored the warning, slipped his fingers under the hem of Derek's shirt and let his hand drift over the hot skin of his stomach. He felt the muscles ripple as Derek growled again, deep and low. It didn't have much of an effect on him any more. It wasn't a real threat, he wasn't going to hurt him and the sound, the sound made the blood run straight to his cock.

"Stiles, not now. Not here."

"Why not?" he asked.

"We're nearly there, I'm driving."

Stiles shrugged and pulled his hand back down, but let it linger in Derek's lap. He brushed his fingers over the bulge the was beginning to form in his jeans. That got a reaction; Derek snapped his head round, his eyes glowing.

"Stiles," he said, before his eyes returned to normal. "Not now."

Stiles grinned and watched Derek turn the wheel, taking the car off of the road onto a smaller dirt path. Stiles wished Derek would just pull over here, maybe drop the seat down again or pull him out of the car and... was the front of the car low enough to fuck him on? He wasn't sure he'd enjoy it up against a tree, it looked good but splinters were just a no. Sure, he wanted their first time together to be somewhere a bit more meaningful, but sometimes he just looked at Derek and he didn't care any more. He just knew that he wanted him.

Stiles flattened his free hand in his own lap, pressing the heel of his palm down against his erection, trying to relieve some of his frustration.

Luckily, it didn't take long to reach their destination. The car pulled up outside Derek's house and he killed the engine.

"So, uh, are we getting out or -"

Derek glared at him before getting out of the car. Stiles watched him walk around the front of the car, not sure what he was supposed to do. When Derek wrenched open the door and pulled him out of his seat, he was glad he hadn't been wearing his belt. Derek slammed the door and then shoved him up against it, kissing him roughly.

Stiles could feel his erection pressing against him, hard enough to make his pulse race. He bucked his hips, aching for some kind of friction but then Derek was walking away from him. Stiles tripped over himself, hurrying to follow Derek towards the house.

They were in the door, up the stairs and on Derek's bed in seconds. Makeshift bed, a mattress on the floor wasn't exactly a bed but Stiles didn't care. All he cared about was Derek's mouth, trailing it's way down his neck.

"You need to learn to keep your mouth shut," Derek said roughly, his teeth pulling at the skin of his neck.

Stiles shuddered. He wasn't really scared of Derek any more, not if he thought about it rationally, but his voice... he could still sound threatening if he wanted to. Stiles liked it.

Derek's nails lengthened against his sides, dragging downwards and shredding his shirt.

"Well I guess that's one way to get me undressed, but I wont have any shirts left if you keep -"

"Stiles, am I going to have to shut you up?" Derek cut in. There was no anger in his voice, but Stiles shut his mouth anyway.

Derek tongue was hot as he licked at Stiles' collarbone, his hands coming up to pull the tatters of fabric away from his torso. Stiles groaned as his teeth grazed over his skin, careful not to break the surface. His research suggested that Derek would have to be fully wolfed out to turn him, but still, his teeth were sharp and he didn't want to accidentally rip his throat out.

Derek moved his mouth back to Stiles' and kissed him slow and deep. Stiles bit down on Derek's bottom lip, hard enough to make the older man growl and thrust against him. The roll of his hips sent a jolt of hot pleasure up Stiles' spine and he hooked his legs around Derek's, forcing them closer. He rocked against him, their cocks sliding over each other under rough denim, stars erupting behind Stiles' closed eyelids.

Just as they began to fall into the rhythm and the friction became way too much and nowhere near enough, Derek pulled away. Stiles was about to complain, but then Derek pulled his shirt off. If Stiles had his way, Derek would never wear a shirt. Or any clothes, really. Well... he did look good in just jeans. Somehow they accentuated his shirtlessness. The denim clung to his cock deliciously; Stiles pushed himself up on his elbows, trying to get close enough to touch him. Derek shook his head, pushed him back down and started to pop the button on his jeans. Stiles couldn't tear his eyes away from his crotch, away from the way his fingers slid over the metal of his zipper. He peeled the denim down and somehow, effortlessly, removed his jeans without standing up. Stiles could barely do that when he was standing.

If he'd thought the jeans looked good, Derek's erection covered only by the thin fabric of his boxer briefs was goddamn perfect. It struck him that he'd never seen him with this little clothing on before, then that he was about to see him naked. His hipbones practically made his mouth water and Stiles let his eyes trace over Derek's body as he slowly peeled down his underwear.

Stiles was convinced he'd never seen anything so perfect.

"Maybe... maybe you do need to find a way to shut me up," he said.

His eyes were fixed on Derek's cock, flushed red and curving up towards his stomach. Derek smirked and moved forwards, swinging his leg over and off of Stiles' body.

"Sit up," he said quietly.

Stiles shuffled up, leaning back against the headrest. Derek slipped his finger under his chin, tilting his head upwards. His eyes were dark as he moved his cock along Stiles' lower lip, before he thrust slowly into his mouth. Stiles fought to steady his breathing as Derek kept moving, cock brushing the back of his throat. He swirled his tongue around the shaft and head, drawing a rough groan from the older man. He focused on his noises, following each grunt and moan to the next. It didn't take long for Derek's breathing to become ragged, but, of course, he'd never let Stiles have that kind of power for long. He pulled back, pushed him back down to the bed and reached over to the pile where he kept most of his belongings.

Stiles watched as Derek found a tube of lubricant. Derek smiled in a way that was kind of hard to read, he wasn't sure if it was supposed to be tender or sexy, but he read it as both. Derek moved between his legs, making Stiles a little nervous. He knew how this worked, of course he did. He researched when he was nervous. Knowing, in the situation, only made it worse. Derek leant down and kissed him, mouth hungry and Stiles tried to forget why he was worried.

He bit back his apprehension and kissed back. He heard the click of the lube cap and bit his lip, readying himself. He'd been waiting for this moment for a long time. Derek's skin was hot against him, a stark contrast to the cold lubricant coating the finger being slowly pressed into him.

Stiles relaxed as Derek pressed another finger into him, opening him up slowly. He felt a shudder as Derek hit something, fingers massaging deep inside of him.

"Fuck..." Stiles breathed, hips bucking up as he arched his back.

At first, it just felt strange, foreign, but before long, the jolts of pleasure began to overtake him. Stiles could feel the heat spreading over his skin as he moaned softly. Derek didn't stop, just kept scissoring his fingers and Stiles was actually considering asking him to stop. He could feel his heart racing, his cock twitching with every brush of his prostate. Just as he opened his mouth, though, Derek slowly slid his fingers out again.

"You ready?" he asked, wrapping his hand around his cock.

Stiles nodded, watching Derek uncap the lube again. He squeezed a generous amount on to his palm and then slid his hand up an down his cock. Stiles couldn't help tensing as Derek lined up. His cock was a lot bigger than his fingers. He bit his lip, forcing himself to be quiet as Derek slowly slid into him. The pain was intense, but his research had told him that once the bad part was over, it was really worth it.

Breathing helped. Eventually the burning ache faded and Derek started to thrust deeper. His eyes flashed red and Stiles' heart rate raced as he felt him move inside of him. Each thrust sent jolts of pleasure up his spine and then Derek wrapped his fingers around his cock and Stiles nearly lost it.

He squeezed his eyes shut, seeing stars and willed himself to calm down. Derek grunted above him and it was nice to know that his werewolf stamina didn't apply to sex with him. Suddenly, Derek pulled out and Stiles almost screamed with the loss. Before he had a chance to complain, though, he was being flipped over.

"Get on your knees," Derek growled.

"Why?" Stiles asked, as he pushed himself up onto his knees.

Derek slid back into him and, wow, okay, that was why. The new position let Derek thrust even deeper. Stiles groaned into the mattress, pushing back onto Derek. He could feel his orgasm approaching, heat spreading under his skin as Derek dug his fingers into his hips. He could feel Derek's cock inside of him, hot and huge. For a second, he thought it might be growing but he knew that wasn't possible. Derek had been fully hard before they'd even started. Then the feeling of expansion continued and he couldn't ignore it any longer. It felt like Derek's cock was swelling at the base, stretching him almost painfully.

"Oh my god, stop, what is that?" Stiles asked, hands scrabbling at the mattress.

He looked round when Derek didn't reply. He looked surprised.

"I... that doesn't usually happen..." he said.

The swelling stopped but the pain didn't as Derek continued to thrust into him.

"Holy fuck... what is it?"

Derek pushed into him hard, pulling at his hips until the swelling slipped into him. Stiles groaned as Derek's thrusts continued, made shallow by the way they were being held together.

"That... that's my knot," Derek groaned.

The pain had turned into a dull ache, but Stiles could barely feel it. The... knot was pressing up against his prostate, making him whimper slightly. He could hear Derek breathing heavily behind him, his hips still snapping forward, even though he was only able to move about an inch inside of him.

Stiles sword loudly as Derek sank his teen into his shoulder, holding him still. The shock ruined Stiles' concentration and as Derek slammed into him one last time, his resolve broke. He came with a broken sob, feeling Derek's cock pulsing inside of him. He would swear he could feel his come flooding into him and he vaguely wondered if werewolves came more than humans.

After nearly a minute, Derek seemed to have stopped but Stiles still couldn't move away from him.

"So... how long does this knot thing usually last?" he asked.

"I don't know, it hasn't happened to me before," Derek replied.

"What do you mean?"

"Well, it's supposed to be anywhere between ten minutes and an hour, depending on the person, but I've never knotted before. It's supposed to happen between... uh... mates."

Stiles felt his face flush at that word. Mate. He'd done his research since Scott had been turned (out of curiosity and boredom) but he hadn't been sure how much of it had been reliable. He'd read that werewolves mated for life, that some never even found their mates. He hadn't given it that much thought and he definitely hadn't thought about him being anyone's mate...

Derek pressed soft kisses to Stiles' neck, running his tongue over the tender skin where he'd bitten him. In the heat of the moment, he'd forgotten about it.

"Derek... did you bite me?" Stiles asked. "Did you break the skin?"

"Sorry. Yeah, just not... I wasn't wolfed out, you're safe."

Stiles breathed out, trying not to make the sigh so obvious. He didn't need to deal with accidentally getting turned, on top of everything else.

He let himself relax as Derek pressed his face into his back. He felt incredibly close to him, but he still hoped the knot would go down soon; the position (and scenario) was kind of awkward.

"So, um, the knot..." Stiles began. "Does that mean..."

"What?"

"Well does that mean we're mates?"

Derek huffed a small amount of air onto the back of his neck. Stiles didn't know if he was laughing or choking.

"I'm not the expert. All I know is it's rare but... I've suspected that you're my mate for a while now."

Stiles felt the pressure begin to ease inside of himself as his face heated again.

"Really?" he asked.

"Yeah... You don't feel it? I haven't had anything like this before," Derek said.

"Well, I don't really have anything to go on," Stiles laughed. "But yeah, I haven't either."

Derek grunted quietly as he pulled out of Stiles slowly. Finally Stiles collapsed onto the bed beneath him, smiling when Derek fell down next to him and wrapped his arms around his waist.

Stiles woke up a few hours later, alone. For a second he panicked, wondering if Derek had bailed on him, but then he heard the running water. He stretched a little before pulling himself off of the bed and walking to the bathroom. It was strangely domestic, but, well, if they were mates, maybe he'd have to get used to it.