Yeah, I'll be your Yoda!

If Stiles was going to be honest with himself, he was going to have to admit: when he dreamed of the day he'd be dating Lydia Martin, he never imagined he'd be sharing her with Derek Hale, of all people...at least not exclusively.

When he first realized she and Derek were dating, it was when he caught Derek dropping her off at school. She got out of the car, kissed him goodbye, and waved as he drove off with a dirty look in Stiles's direction. That had been just after the sacrifice, and he was a little raw for a while after that. Losing out to Jackson Whittemore was one thing, and he knew she didn't give a rat's ass about the guys she slept around with at school. Derek, though...Derek was pack, and so it bothered Stiles. It bothered him a lot.

Then the day came when she sat next to him at lunch, and put her hand on his thigh.

One thing lead to another, and soon they were in Coach's office, groping heavily and breathing just as heavily until Stiles came just enough to his senses to stop kissing her neck and remove his hand from under her shirt.

"Aren't you and Derek...together?"

It took her a long moment and a dirty look, but she finally raked her hair back from her face...and did that thing with her mouth that he'd noticed more than once before, usually after he admitted something he probably shouldn't have. Like he'd shopped for her intensely, or admire her cleverness, or that he believed in her to his own detriment.

"Yes. I'll be honest. But...I need more than he can give me, and we've talked about it. It's a whole...human/werewolf thing. And he's not...you. And you, Stiles, you're just..."

She trailed off, and that thing happened to her mouth again, rolling her lips as if she could keep something in by sealing them tight.

When she kissed him again, it felt...different. Different in the way Stiles had always dreamed of, different like he was finally not just visible, but vital to her.

He didn't pull away from her again.

As they started fooling around during school, Stiles learned that she'd started with Derek during one of the full moons, catching him in a bad moment and using sex to get him through a lapse in control. From there, they'd developed into something more, but he held back a lot in ways Lydia couldn't deal with. They did love each other, too much to break up, so Lydia offered an alternative and Derek agreed: she could bring someone else in with Derek's blessing, but only someone within the pack.

Stiles wondered if Derek knew Lydia had probably figured out precisely how to get Stiles, in particular, into the equation the day she made the deal.

He didn't quite believe the whole thing was real until the day she brought him to Derek's place to fool around in his bed.

"It's better this way, just...have him catch your scent on the sheets. Get him used to the idea." she swore between kisses as she pushed him back, straddled his waist, and slid her hands under his shirt to brush her fingers up his stomach and chest, nails kissing his nipples as she mouthed his jaw and ground against him.

After they fucked in his bed, the next time Stiles saw Derek in person, he was...shockingly deferential. He got a lot of sour looks, but after the group hooked up to talk about the problems that Scott, Allison, and Stiles himself were having with nightmares and hallucinations, Derek actually found him after and offered him an ear if he ever needed to talk.

"It's...a pack thing." Lydia gasped as Stiles was going down on her in his own bedroom the next weekend his Dad had a double shift and the house was empty. "In his eyes...you're higher in...the pack...as Scott's best friend...right there, do that again! Oh God, oh God..."

Later, as the insomnia and anxiety got worse, as the trio kept dancing around each other without ever really connecting, Lydia finally started insisting they spend time together. It was...weirdly cool, lounging around Derek's loft together. Lydia's favorite pastime was studying, watching TV (which she'd forced Derek to finally get), or just reading for fun with her head in Stiles's lap and her legs draped across Derek's, both boys sitting side by side. It was oddly comfortable, and Stiles thought he might be crazy, but the pack bonds Derek, Isaac, and Scott were always talking about...Stiles swore he could feel them in those moments, warm little bands of comfort linking them all as one. It even let him sleep a little more often, the two of them carefully sliding away when he got drowsy so they didn't disturb him...and Derek carrying him to bed.

Stiles would have been annoyed if he hadn't been so tired.

They had been hanging out together for a week or two the night Lydia tried to take the final step: getting into bed with them both at the same time.

Stiles was studying for an Econ exam while Lydia read something by Stephen Hawking and Derek read...whatever Derek liked to read when Lydia suddenly reached up to pluck Stiles's book out of his hands and caught his shirt in her fist, pulling him down for a kiss. Too shocked to respond, he just let her until she finally let him up.

His first act was to look to Derek...who was staring at them with something so hot, so visceral in his eyes that it made Stiles's cock twitch in his pants. He also became aware that Lydia had kicked off one of her heels and was slowly, gently grinding her heel into Derek's groin, toes wandering now and again to trace the visible length of his growing hard on.

Mouth dry as a bone and flush with arousal, it was all the motivation Stiles needed to lean down and kiss Lydia without any further prompting.