Girls kicking boys in the balls was pretty common at my high school. I feel like it's common in general at that age in fights or because girls think it's funny or whatever.
Anyway, this all happened over some dumb shit. One of my friends was going around telling other guys this one girl was flat chested. For some reason the girl thought it was me saying it. She confronted me about it saying she would get fuck me up etc etc. I think I laughed at her and didn't take it very seriously as she was just this small girl and it wasn't even me.
A few days later, as I was standing talking to a few friends, she walked straight up to me and kicked me as hard as she could between the legs before I could react.
I must have been on the ground for 15 minutes, rolling around and sobbing for most of it. I literally cried I was in so much pain. Little bitch kicked my poor balls so fucking hard.
I limped home and was in bed for most of the next few days, cradling an ice pack to get the swelling and bruising on my testicles to go down.
That was 15 yrs ago. My left ball never hung the same way again, it's lopsided and I developed a small hydrocele on it shortly after. My scrotum definitely sagged more after I recovered also.
Fucking bitch. She wasn't punished by the school or anything which was fucked up, as they heard the rumors that were being spread.
I count myself lucky I still have both balls I guess. Everything still works. I will admit that this experience of having my manhood attacked by a girl and feeling defenseless was definitely one of the formative ones that got me interested in the ballbusting fetish, assuming it's the same for many others.
To clarify -
1) it was the last year of high school, we were both were 18 at the time.
2) some people will assume it's a fake story, so I would say that you can see evidence of what i'm talking about in a few of my nsfw pics.