If your partner asked you to bite her thigh hard enough that she slightly bleeds or just get bruised, would you do it?
Of course, it can be dangerous. But it can also be practised safely. Believe me, I know.
For men who are (rightfully) scared of crazy women who might use this to claim rape or physical abuse: She signs a consent form and also videos herself consenting to what exactly she wants (with all the details). So?
Superb Opinion