I was talking with my uncle yesterday while watching fireworks and i heard a story that you all might find interesting.
My 10 year old cousin was riding his bike down the street and decided to pop a wheelie. When he did, he went to far back, so to avoid being crushed by the bike he tried to jump off. In the process he caught his scrotum on the seat... tearing an inch long hole in it and then the bike crushed him.
i pop a wheelie on a trail by my place and had the front wheel in the air for a while then i pushed on the peddle a little hard and the bike kicked out from under me and i landed flat on my back. it knocked the fucking shit out of me
I remember when i was about 10, my best friend in my class was into BMX'ing and doing jumps on bikes. He was on a half-pipe and he fell and the damn handle bars went right through his cheek...don't ask me how. He had to get it sewed up and he has a scar there (BS meter is on 0)
I've done the wheelie thing/go over backwards. Nuts stayed clear though.
Stoppies.. stoppies are great. I do em on my mtn bike (and my dirtbike, heh. Little harder on that)
If you go over on a stoppie on a mtn bike, you can land on your feet, no problem. If you do it on a dirtbike... well, its not as fun, I'll tell you that.