A direct derivative of piss battle. This type of battle was created when two piss battle combatants had a draw...that is, both bladders were burst. Neither contestant wanted to cease the battle so they decided to join their rectums in order to have a battle of the anal muscles.
1. The combatants join their anal cavities together and after forming an leaktight seal begin to push the defecate between eachother. These battles are often ended once one of the combatants has emptied their body of all defecate. At this moment the combatant may disconnect their anus from their opponent and claim victory.
Shit battles are epic.
Shit battles do not cause cancer.