The following is an exerpt from the book War Story by Jim Morris. Morris was assaulting a hill with a company of Nungs and an Australian advisor when he is hit in the left testicle.
"It was a slapping sting, really hard, and then it went numb. The thing, I think, that stopped me from pursuing this matter any further was something I had read, or heard somewhere, about your testicles being made up of thousands of feet of tiny filaments all rolled up in a ball in your scrotum. I got this rapid mental image of my scrotum being broken and all those filaments rolling out as I tried to charge on up that hill. I saw them thin as thread, pink and glittering, dragging down in the mud, and me charging the hill, stepping on them in my cleated jungle boots, stopping my own rapid charge with a jerk. Yes, I belive that mental image did it. I lost all interest in personally taking that hill at that moment."
And a few paragraphs later.
"We skinned down my pants for a look. It was very strange. The trousers were covered with blood, but they were not broken. Apparently the round had just plowed a furrow across my pants. If I'd been wearing jockey shorts it wouldn't have touched me at all. But as it was there was complete trauma and the scrotum was swollen and bruised black all over. It looked like a rather large eggplant covered with blond hair. My poor little penis, on the other hand, had shriveled almost to the point of disappearance. Another inch and it would have been concave."
If you haven't read War Story by Jim Morris....make it a point to.