What would you do?

Ouch!

What is a guy to do under these circumstances?

You broke up with your ex and now you're both at some party. She is pissed off and pissed and wants you to shag her. You could have complied grudgingly. But then she would think there is still hope for you two.

You refuse, knowing she is a right nutcase. She proceeds to rip one of your nuts off. Then puts it in her mouth. Then spits it out. Then have your friend pick it up and hands it back to you, as you bleed and scream in agony.