It's where you get first place in Kahoot and print out the sheet and then crumble it up and shove it up you're ass. You must leave it in for as long as you can go without shitting, then shit it out in your math class.
First and foremost it is not just any booty, hence the KA in kabooty. It is the be all, end all when it comes to the ass. It is a tight, round, large backside that you not only could bounce a quarter off of.....it is visually a site of ass perfection. Straight Kabooooooty. Because of the ramification of the word, it can be used sparingly in key times when something is metaphorically like a kabooty. For instance if you happen to have a stellar evening and get a lap dance from a midget in a random bar while you were hammered with friends, the event might be considered a "Kabooty" event.