Post it, Smiral. 

I was trying to remember some that didn't involve sex that would be safe to post. I got one. 

I was about 20 or so, and my friends and I went to a big outdoor concert that Disturbed was headlining. At the time I was trying to lose some weight so I was taking these pills called Zantrex and sometimes they could cause uh...stomach upset. So we're all moshing and having a good ole time and suddenly I start to get the bubble guts. Oh shit. Run to the portapotties. Goddamnit Disturbed is taking the stage. I find an empty one and lock myself in. I'm dying. It's so hot and it smells like a litter box. A couple are in the portojohn next to me getting it on, I can hear the rhythmic thumping. So I'm stuck in there, stomach cramping and you can guess the rest. I can hear the song 'Down With the Sickness' playing and I was like, "Yes I am." :( 

I was stuck in there most of their set. Finally get out on the last two songs and after the show my friends were looking for me. Had to tell them where I was. They laughed and made fun of me the rest of the day.

TL;DR I got to a big concert and get the shits and miss the headlining band while in the portapotty.