An Educational Experience
Lesson 2: Ball Punching/Ball Smacking
Punching can be much more dangerous than slapping or not if you are smart about it. Never punch the testicles into anything. Do not place them against a wall or some other object and hit them into it. So long as the testicles are allowed to swing they will redirect the energy in the blow. The testicles will also move away from the punch on contact so that it is next to impossible to hit them dead on so long as they can swing away. There is no chance that you could hurt the testicles by punching them. It does not matter if the punch comes from the front or behind.
If you hold the testicles in your hand so that they cannot move you will run into that 60psi limit once again. A strong heavyweight professor boxer can punch at around 300psi without gloves. The average man would be doing good to get 60psi while punching his own hand. It would take a really strong woman to be able to punch a testicle in her hand at 60psi. Unless you are a strong woman you do not need to worry about hurting him in this way. If you are a strong woman avoid punching as hard as you can. It is unlikely that a strong woman could even achieve 60psi unless she was super strong but just to be on the safe side strong women should avoid punching as hard as they can when punching testicles in their hands.
The third punching method is the uppercut punch. Punching the testicles up and because the testicles might hit the body the same 60psi limit applies. Unless you are a strong woman you do not need to worry about it. If you are then do not punch as hard as you can. Alternatively, you could punch the testicles up but not into the body and because they are allowed to swing the testicles will not be harmed no matter how hard you punch.
To summarize, so long as the testicles are not punched into anything you can punch as hard as you want. If you do punch the testicles into something strong woman should not much as hard as they can.