A/N: I'm kind of surprised that so many people liked the Stiles one-shot. I hope I don't disappoint you with Derek's. I am currently working on an actual story, though I have no idea when I'll be posting it and whatnot. I do have other stories already in progress, and they kind of take precedence over the one in development. Anyway, thanks for all of the support! R&R. Enjoy!

Cousin Miguel

Derek

He was sitting on the chair in Stiles' room, reading, when he first smelled it. It was a unique scent, one that he had come across more times than he ever cared to remember: the scent of arousal. And it was coming closer to the house and it was accompanied by Stiles' own scent. Actually, to be precise, it was enveloping Stiles' scent; wrapping around it and suffocating it.

Derek growled, both him and his wolf feeling restless and irritated. Whoever it was that was aroused and near Stiles better leave before they over stayed their welcome. Stiles was his mate. His and no one else's. So whoever it was that was so aroused by his mate, they better get lost, and fast.

The door opened and he heard Stiles' voice followed by another's. One that he didn't recognize; the one that owned the aroused scent. He snarled and nearly leapt up from his seat when he forced himself to calm down. Taking a deep breath, Derek forced his wolf, and himself, to relax and gain some sort of composure. Before Stiles left for school this morning, he did say something about possibly getting a friend to help him with that mysterious text message. But he didn't say that that 'friend' would be so interested in him…

By the time Stiles and his friend had entered the bedroom, Derek was as composed as he could be, with his nose back in his book. Glancing up at them out of the corner of his eye, he saw that Stiles' friend was the goalie of the lacrosse team. He had seen him when he went to a few of their games to observe Scott, but he had no idea that he was into Stiles. Even thinking about the possibility that another person was attracted to Stiles made him want to kill something.

He could barely suppress the growl that emitted from his throat when the other teen sat down next to Stiles. They were supposed to be doing lab work, but Stiles was trying, and failing miserably, to get his partner to trace the mysterious text message that Scott had, apparently, sent Allison.

"Who's he again?" Derek didn't look up; he just kept on skimming over the same page he had been reading when he first smelled the aroused scent. If he wasn't so preoccupied with making sure that the new kid didn't touch his Stiles, he would have laughed at some of the ridiculous crap the book had on werewolves. But he was merely using the book as a distraction, both for himself and for the goalie.

"Oh… That's my cousin… Miguel." Well, that was…a new one. Of all of the names Stiles could have chosen, he picked that one? Looking up, his eyes bore into the back of Stiles' head before they briefly ventured over to the goalie. He was watching Stiles intently, and he was sitting way too close to him for Derek's liking.

"Is that blood on his shirt?" Derek could hear the protective tone in the goalie's voice, almost as if the teen though he'd actually be able to protect Stiles from the likes of him. Ha! The only thing the kid was good at protecting was his goal net. Stiles was Derek's, and the werewolf was more than capable enough to protect him.

"Uh… Y-yeah. Miguel gets these massive nosebleeds. It's really embarrassing. Hey Miguel, why don't you change your shirt?"

Derek's eyes met Stiles' for a split second, and he nearly smirked when he saw the lust and desire in them. But he didn't smirk. Danny, or whatever his name was, glanced over at Stiles as Derek stood up and took off his shirt. He did smirk then, as he was faced away from them and opening one of the drawers in Stiles' dresser. Sure, Danny was physically fit – he had to be in order to be the goalie for the lacrosse team – but he had nothing on Derek, and the wolf knew that. Judging by the slight smell of jealous that now tinted Danny's scent, along with his arousal, Derek figured that the goalie knew this as well. His small victory was taken from him, however, when I picked up one of Stiles' shirts. A frown quickly made its way onto his face before it turned into an expression of outright irritation. Turning around to face the two teens, he saw that Danny and Stiles were sort of huddled close together and looking at something on the computer screen. This didn't help Derek's irritation. Not one bit.

"Stiles. This? No fit."

Stiles didn't turn around to face him, but he didn't have to. Derek smelled his fear and slight panic, and it made him feel a little bad. After all, his irritation wasn't exactly Stiles' fault; he was already irritated when his mate brought Danny over. Frowning, wanting to reassure the boy that he wasn't mad at him, Derek made quick eye contact with Danny, who was looking him over with envy as he scooted a bit closer to Stiles. Derek had to fight to stop growling.

"Then try something else on."

If he could, he would have growled. That comment, though typical of Stiles, didn't help Derek in his quest to intimidate and ultimately get rid of Danny. Glaring at the tanner teen and Stiles, Derek grabbed another shirt, barely even looking at it before putting it on. It was tight, though that really shouldn't have been all that surprising, seeing as how it was Stiles' shirt after all. He glared at Stiles and Danny both, particularly Danny, as the taller teen was trying, and failing, to remain unaffected by Derek. He sensed a mood change then; one of not only arousal, but something else.

"Yeah. Hey Danny, doesn't that look good on him?"

Inwardly, Derek groaned. Stiles, although his mate, was a moron. He thought that Danny was making goo-goo eyes at Derek when, actually, he was sizing him up, judging to see if he had a fighting chance. Naturally, he didn't, and Derek felt more than pleased with himself when Danny lowered his gaze. Good. The boy needed to be taught his place. However, Derek couldn't focus too much on him because Stiles was practically radiating sexual desire. Smelling such a strong scent coming from his mate made his wolf whine and pace, wanting to be closer to its mate. But he couldn't; not at that moment in time, anyway.

"That's…uh, not really his color."

Suppressing the urge to shake his head, Derek took the shirt off and placed it backed where it belonged before he grabbed his own shirt and sat back down, picking the book back up. He skimmed over the pages as the two teens hunkered down by the laptop, Danny fast at work tracing the text message. Not long after that, Danny had successfully traced the text message, and Derek had to stop the shock, dread, and confusion from over flowing. Beacon Hills Hospital? Specifically from Scott's mother's computer? What was going on?

He had plenty of time to think about it while Danny and Stiles worked on their lab stuff. The goalie didn't leave until it was dark outside, and as soon as he was gone from the immediate vicinity of the house, Derek practically dragged Stiles out of his chair and hauled him downstairs and outside to the jeep. It was quiet and uncomfortable on the drive to the hospital. His thoughts drifted from what was going on with the text message back to Danny and Stiles. Derek could honestly say that it felt like a weight had been lifted when Danny left. Never before has he felt this way, but then again, he didn't know who his mate was until recently. And now that he knew who it was, he didn't want to lose him.

Regardless of the fact that Stiles was a sixteen year old boy, a very talkative sixteen year old boy, and was, basically, Stiles, Derek was overjoyed at having found his mate. Hell, if he was honest with himself, he actually didn't mind that Stiles was talkative, hyper active, a bit annoying, and a boy. Actually, he kind of liked all of those things about him, and then some. Stiles was loyal, and smart, brave and a good kid. And although Derek wasn't the worst person on the planet, he wasn't the best either, and he was still shocked that he was good enough to even have a mate. Lord knows, he thought he didn't deserve one, after the stupid shit he pulled…

He was jarred out of his thoughts when he inhaled deeply and took in Stiles' scent. The teen was still aroused, but not as much as he had been in his bedroom, and Derek could faintly, very faintly, detect a whiff of Danny's scent on him. That made him growl.

"Who was that guy?" Stiles' heart quickened its pace as the teen pulled into a parking space near the Long Term Care Center and parked the jeep.

"Uh, that was…was Danny. He's my lab partner for Chemistry and he's the goalie for our lacrosse team. Why?" Derek's green eyes were focused dead ahead as he glared at the building before them, his wolf and himself both angry at the fact that Danny's scent was on their mate.

"I don't like him. Don't bring him over and stop hanging out with him." Somewhere, deep down inside, Derek knew he was being unreasonable, and he didn't give a shit. Reason went out the God damned window when he breathed in that goalie's scent. Stiles jerked and Derek could smell anger, fear, and irritation rolling off of his mate.

"What? No way! Danny's m-my friend and lab partner. And he's the goalie for our team, so I can't stop hanging out with him. You know what? Just because you're a big, bad, scary werewolf doesn't give you the right to boss me around and shit like that. You're staying with me because of Scott being, well, Scott, so you should be grateful or whatever. And that means, uh, you shouldn't…boss me…around?" Stiles was out of steam by the time he had finished, and Derek found it oddly cute. Just thinking about Stiles wanting anyone else aside from him made him growl and he quickly moved so that he was pressing Stiles against the driver's side door.

"Do you know that Danny, or whatever his name is, likes you?" The dumbfounded look on Stiles' face was endearing, and Derek felt his wolf hum as it itched to be even closer to the boy who had captivated it.

"Huh?" Instead of groaning or growling, Derek opted for an eye roll.

"Before the two of you even entered the house, I smelled him. More specifically, I smelled his arousal and, believe me, it wasn't me that was making him all hot and bothered. His heart was beating faster than it normally should've been and, just in case you didn't notice, he stayed close to you when the two of you were working on your lab bullshit. So yeah, I think it's safe to say that he likes you. So stay away from him."

"W-w-what? But that can't… Danny doesn't… He's my friend! I can't…" Growling, Derek pressed his lips to Stiles in a bruising kiss, his wolf and himself both feeling more content and satisfied than earlier that afternoon when Danny had showed up. Much to his satisfaction, Stiles eagerly responded to the kiss, and he hummed, feeling relieved and happy. Pulling away, he gazed at Stiles as he spoke, making sure that his point was driven home.

"You are mine. Not his. Mine. Got it?" He smirked when Stiles nodded, looking bewildered and confused and aroused all at once.

"You're my mate, Stiles, not his. Do you have a problem with that?"

"N-no." He kissed Stiles again, wanting nothing more than to continue kissing him – among other things – and just wanting to be closer to his mate in general. But, they had a job to do, and as much as he'd rather just stay here with Stiles, that just couldn't happen.

"Good. Now, call Scott and see what he found out."

Stiles was his mate, not Danny's, and he was safe. That's all he could ask for.