It was embarrassing how quickly the pleasure built, how tight his balls became once he was allowed to fuck Derek's mouth. Stiles let out a strangled noise, he hit his head against the floor once, as he struggled to get out. "I'm... fuck... I'm close," Stiles gasped and his hands tightened their grip on Derek's hair, his nails digging into the werewolf's scalp, before he cried out. Stiles came down Derek's throat, his body tense for a moment before everything came undone and Stiles started to tremble.