My bf is a hypnofetishist (whew, that's a mouthful.) In general, the idea of mind control makes me want to puke, but I've agreed to play with hypnosis in really minor ways that he finds arousing (tricks like, I'll wake up and go about my business and be just about to leave for work, but my hand touches the doorknob and I suddenly realize I've got no clothes on).
I can't help adding the obvious: if you're going to play for real with mc, BE CAREFUL - when you're under, your inhibitions are very low and you're more likely to say and do things you wouldn't do otherwise. Speaking from experience, even if the boundary-crossing was probably an accident, you feel like your trust has been violated in the worst possible way. Be very clear beforehand on what kinds of things can be asked and done. Asking a hypnotized sub questions about limits and consent is not fair.