Alot of the responses here deal with cutting.

My fantasy is about losing my balls through a harsh squeeze.

One of my fantasies is being in a fight with a very violent/angry woman and that we go to ground and really wrestle (her skirt riding up her brests pressing into me etc....) This goes on for a while and then I get a good hold on her and she struggles and when I think that I have her, she manages to get one or both of my nuts in a terrible grip and now it is whoever gives in first to loose.

She squeezes harder and harder and as I weaken and begin to loose my grip on her she gets stronger till eventually I have to let go and she slowly crushes them in her hands