When out of nowhere your stomach gets pissed off, resulting in rank farts and an immediate need to drop a deuce. Often occurs while on post with no way to address the issue, so you just Kung Fu grip the Hesco barrier and ride the storm until your relief shows up several hours later.

I ate Taco Bell after a week of eating MREs in the field and got the bubble guts so bad I almost shit myself before we got back to the barracks.