ive had this happen to me, but i had a bit of a complication... the tube which connects your testicles to the penis (the vas defrens) got twisted when my nuts popped inside me. and boy can i tell you ive never been in so much pain in my life, seriously, its about the equal pain to what id immagine birth to be from the education videos ive seen of birth. had the get it opperated on, so now i have a nice littel scar on my sac, and my one ball is significantly lower than the other.