This is a stupid, but serious question.
 

I was thinking about it today, are you allowed to use your athletic cup to strike your opponent? Example being in north south, for lack of a better word, face **** your opponent? Because a lot of guys use a steel cup and I'm pretty sure that would do a lot of damage. I just know when I'm rolling in my jitz class, and a guy decides to put his cup in your face, it sucks.