Derek pulled back, studied Stiles' blush. "Well...those are all things that I enjoy," he admitted, slowly. "But you can be different. You don't have to wear a plug, if you don't want to. With as much physical activity as you do, I can't imagine it'd be comfortable." His hands curled around Stiles' hips, and then to his backside, kneading his cheeks through his pants. "As for being an eager slut...I want you to enjoy what we do and not be ashamed of it, or feel bad because of it. But I use words like slut and whore because Isaac was conditioned to respond to them, and when I say them, it lessens the shame he used to feel. Do you understand?" He held the boy's gaze, seriously. "If I call you my slut, if I say that you take cock like a whore...it's meant to arouse, not to humiliate."