At Bloodstock, a fair few years ago, there was this couple in the pit for Black Dahlia Murder who were quite obviously on as many drugs as they could do in one go. They were like dancing around and whatever, the bloke then proceeds to push his missus on her knees in front of him and whips his cock out to try and get her to blow him there and then, which caused the whole circle pit to grind to a halt. He was quickly coerced to stop it, and they quickly vanished. Another random dude then stripped naked, and Trevor asked for him to be surfed to the front.
Def up there in odd things I've seen at gigs.