refering to or having a large, or king size, amount of the fast food in your large intestine, making it's way out through the anus. Giving one relief that they did indeed have it their way.
A large woman or man that eat a lot of Burger King and that is their fast food of choice. A connoisseur if you will of Burger King.
Dammmmmmmmm that bitch got one big Buger King Butt..
SHIT my Burger King Butt is acting up again!
Oh no, I got no control over my Burger King Butt!
That guys works hard on his Burger King Butt, he eats it everyday for lunch!