The instructor on the first aid course I was on told us of a horrific mishap he saw when one of us asked him about resetting dislocated limbs. He'd been playing rugby and one of his team mates had been tackled hard, dislocating his femur so they decided to reset it while waiting for the ambulance. (For those of a nervous disposition or male I've whited this next bit out, if you do want to read it just highlight it.) Unfortunately they managed to trap one of his testicles in the joint At that point the poor bugger started screaming so loudly he ripped his larynx.
Was he playing for Dorking? - it's just that we had a similar event about 20 years ago when I was playing. I've never heard a man scream like that. It chilled me to the bone.
Similarly, on another occasion, a chap took a good blow to the gentleman vegetable area. Massive swelling ensued and by the time St. John turned up his sack was the size of a melon. they had no choice other than to relieve the pressure. He howled a bit too.
I gave up rugby shortly after.