It takes him by surprise when the teenager is suddenly moving in, and there's a moment where he's not sure what Stiles is intending; using Derek's own tactics and physically pushing him of something else. But then their mouths collide as Stiles drags him down into the kiss. It's an answer, if not the one he was expecting. He responds as soon as their lips touch, with a hint of a growl in the back of his throat. He catches a hand in Stiles' shirt, and there's a brief thought of pushing him away.

This is reckless, dangerous, everyone he cares about gets hurt or hurts the people he cares about and he can't stand the thought of that happening to Stiles. But this has been a long time coming, and somehow Stiles feels safe. He knows Stiles wouldd never hurt someone, but he's still worried that the boy will get hurt, but he still pulls him in a little closer. And that's about the moment both he realizes that stupid and selfish as it is, he's not leaving with Cora.

He wants to talk him out of it, tell him exactly how stupid getting involved with him is, even wanting him. But, for the moment at least, he can't stop kissing Stiles, lips warm. Stiles is always going to be Stiles, he can believe in that and not worry about this turning into another Kate, another Jennifer.