I have like, the inverse of this. I want to watch a very shy, cute guy who's normally very prudish tell me about his kinks, and revel in his shame. I want to see a "pure" person's dirty, corrupt side.
Then, I'd probably want to bully him for being a sick freak, only to let him indulge in his fantasies with me. Depending on what it is, I'd either just dirty talk with him while giving him a handjob, or I'd let him actually try it.
Bonus points if the whole thing messes him up mentally and he has an obsessive love/hate relationship with me after the fact.