Stiles makes a frustrated noise, his head falling back to the pillow as Derek turns his attention to his neck and shoulder, and he concentrates on breathing, because his body is used to getting off as quickly as possible, and he'd never seen a reason to not before. But he thinks he might get it now, because he could be completely content to stay like this forever.
They might not be naked, but they're close, and all this skin-to-skin contact is new, his brain not sure how the sensory input, from the heat of Derek's skin to the light fuzz of body hair.
He moans Derek's name, his hands moving up the long column of his back, restless. "Derek. God...Derek. I can't...."