It would be so easy. Look at the height at which he’s laid him across that car, with a free hand to spare! A free hand that, frankly, I don’t understand -not- using to unzip his pants, pull out his cock and shove it right in that precious boy’s face.
Right in that precious boy’s mouth.
And Stiles never keeps his mouth shut long anyway, but that doesn’t mean it isn’t a pleasure to force it open a little, sliding a thumb across his bottom lip and teasing until he can’t help but trying to talk and then pushing it between his teeth, pressing down his tongue.
He never keeps his mouth shut - it’s probably one of the first things Peter ever thought about Stiles. ‘Need to stuff something in that little bastard’s mouth.’
This wasn’t what he had in mind. But now that he’s got him here, now that they’re alone and remote, now that Stiles’s helplessly frustrated face is just inches away from his lap … Peter can’t exactly complain. He’ll get him to be quiet, and he’ll get something else, too.
With the first thrust he makes over the vaguely resistant reply Stiles was preparing, the one that opened him up for Peter to force his way in, he drags his thumb up across Stiles’s cheek. He’s suspended somewhere between sheer, simple pleasure and his natural condescension for this irrepressible smartass. Heat and wetness feel good, but shutting him up feels incredible.
He waits until there’s no more struggle, just the instinctive adjustment of mouth around cock, and tells him, “That’s it. That’s better.”
And Stiles’s eyes are nothing but contempt and hatred, but he’s not exactly trying to break free, is he?