Derek’s literally, literally about to come, when they hear the sound of a car engine rounding the corner. Stiles’ hand tightens around Derek as he pulls off, and that’s enough to send Derek over the edge, coming over Stiles’ open mouth and his chin.
They’re both frozen in shock for a long moment. ”At least we can cross that off our bucket list?” Derek tries weakly. He can’t move, it feels like Stiles sucked his spine out of his dick and his whole body is jelly. “I heard it’s good for your skin?”
"Why are you saying that like a fucking question. Shit," Stiles swears, his voice horrified. "Oh my god, Derek, get out of here!” Derek stares at him, and his eyes glaze over at the sight of Stiles wiping come off his face and sucking it off his fingers. “Go,” Stiles says again, shoving at Derek, and neither of them is expecting the way Derek goes toppling off the side of the porch, falling into the bushes. “Derek, what the fuck?”
Derek waves his hand dismissively, unwilling to tell Stiles that his blowjobs are so good that he needs at least 3 minutes of recovery time before he can move again. “You still have come on your face,” he hisses back and Stiles meeps, scrubs at his face vigorously.
"Is it gone?" he asks, and Derek nods, before ducking down just as the cruiser pulls into the driveway. "Fuck," Stiles says again, before turning to his father and Deputy Parrish. "Dad, Deputy," he greets with a pained grimace.