I did this to my ex husband…As we were going through the divorce process he turned really nasty and started to brag about all the other women he fucked around with while we were married. I pointed the bony witch finger at him and stated with every conviction of my being that he didn’t deserve to have a dick and I cursed him that it would fall off. 3 days later he was rushed to the emergency room and had to have emergency surgery on his dick. In a matter of 3 days he had grown such a large cyst on his dick it was cutting off the blood flow… Teehee.
You could always just put his dick in the freezer and make him impotent as well. That trick always works a treat