8th grade gym class. I was doing a sit up and my friend Cindy was holding my feet. I was laying down and as I came into the "up" position I farted. Fortunately nobody heard me....that is until Cindy said very loudly "DID YOU JUST FART??!!" At that point everyone stopped what they were doing and looked at me. You could have heard a pin drop.
I just blushed and said "yeah, well I'm doing a fucking sit up!"