A bowl movement, jobbie, or crap session of such intensity that it is measured to the power of one million standard craps. Such is the magnitude and intensity of a mega grunty that it can be beyind the capability of the average colorectal system and therefore a mega grunty may need to be delivered by cesarean section. A mega gruntie can be both intense and satisfying and can therefore result in a backdoorgasm.
"Sorry to take so long, I was almost torn in half at the seams by a massive mega gruntie!"
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).