Derek smiled a little as Stiles went boneless in his arms. His slave was solidly built, even if he was still growing into himself. He doubted he would get much larger than Isaac, but he still had some filling out to do.
He laid the boy in the tub and then turned on the water, pleased to see it was still mostly warm from his shower. He adjusted the temperature and then hung up his towel before climbing in the tub behind Stiles, letting the boy's back fall against his chest, his head loll against his shoulder.
"Gonna fall asleep on me?" he teased, pressed a soft kiss against the boy's shoulders. He was...relieved, and tired himself, from their earlier fight and then the exertion after. "Come on, Stiles. The sooner you get clean, the sooner we can go to bed."