The attack of poo on the outskirts of the rectum that is so violent that you can feel the anus veins pulsing faster and faster until the bum blasts out the rumbling poo at the speed of light and the bumhole starts foaming with steam, leaving the pooer wondering whether that they just released a bubbling, mutant fart or a hard, moist poo.
The bum battle
Person 1: I just had the most awesome bum battle ever
Person 2: was it a fart or a poo
Person 1: I still not quite sure. The toilet's in a bit of a mess