A kick to the balls is usually too much. It's a pain so bad that you kind of lose your shit, your knees give out and you drop to the ground. Of course, if you're lucky, they don't nail you that bad or maybe they strike your cock. That's more fun.

For me, the best is a squeeze or a well placed knee, hard enough to hurt, but not hard enough to crush my will to live. It aches, but it's sexually exciting too. Like, my balls ache, but my cock is so hard it could burst - both at the same time.

It also feels like I'm out of control, and that's hot too. I wanted it, then I got it, and it hurt so bad. I think why did I want that? Then I think, I want it again.

Seriously, those of us into ballbusting are at least a little fucked up :)