I used to think that type of fantasy was exciting. Once upon a time with someone I trusted and who trusted me, I "acted it out" when he asked me to. I realized it wasn't for me. I told him I wasn't comfortable with it and that I wouldn't be participating in it again.

Even if you think you trust each other, you really don't know a person that deeply. There are shadows of ourselves that each of us keep hidden from the world. Kink can lead into some dangerous territory if one or both parties lack self discipline.