I’ve done some knife play in the past, and it was fun. She didn’t cut me; she dragged the knife across my skin with varying amounts of force. It was a good addition to the scene every time, but it didn’t give me the massive chills or fear that others get from knife play.
The reason is that for me to do knife play with someone, I need to trust her. I won’t put myself in that situation with someone I know isn’t worthy of that level of trust. But if I do trust her on that level, then I know she won’t do any damage or go too far with it. I’ve been tied down, with a knife to my throat or my cock, but I knew she wasn’t going to un-penis me or slit my throat. So there is no fear there, only trust. If she did damage me in some way (or did a mindfuck to make me think she was damaging me) I’d be very unlikely to ever put myself in that situation with her again.
Knives are sexy, as is the power that comes with them. Still, the appeal of knife play for many people is the fear aspect. And that fear just isn’t there for me with someone I trust. But that’s okay- there are plenty of other nasty, painful, disgusting, humiliating things that can be done in bdsm.