Duro ballbusting. CBT

His balls in my hand are quite defenseless. In my dominance over the man, I can be so mean. I also know exactly where my strength is best used to hit him. His ball is already very swollen and extremely sensitive at every touch. His balls have a lot to take, cause I always grab them very harshly. 
A clutch on the balls, a squeeze in my hands, or the hitting on the balls... it all works. It is especially bad because he can not even see the game. I also tie the balls tightly, so I have them under better control, I can squeeze them firmly and he can not tear them off. He has to accept what I am doing to him.