Its actually really hard to score a direct hit on the nads in a fight. Most guys are somewhat expecting it and the motion itself is a giveaway. All it takes to thwart a nuttap is for the defender to shift his body slightyly and a damaging nut hit becomes a not at all painful kick to the thigh, leaving you off balance and your opponent in a pretty good position to hurt you.
I didn't make it!
hit him/her in the toe, it would break it, but not for ever
ah just knee capp him that will put him down for a while