If you are going to try and wrack someone in the groin, do not try to kick them.

First, contrary to most men's opinion of themselves, the groin is not that big of a target. It is also fairly well protected by two of the heaviest and densest bones and muscle groups (the thighs). If you should miss, which is more likely than you think, all you will do is hit someone really hard in the inner thigh. That will not hurt them at all, and will telegraph what you were trying to do, which will piss them off.

If you want to go for the groin, use a palm strike instead of a kick. And after you palm strike, don't stop. Then you grab. Tight. With everything you have. You grab hold and you keep squeezing as if your life depends on it. You take those puppies home with you if you have to. Someone who wishes you ill will does not get their nuts back until one of you is unconscious.