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1.
Any square ass loser who always be floorin his v-tec and parking it in reverse, and who wont play outdoor basketball because he might get sick
This SquareButt Ri Hea (refer to picture)
by Pimp McPimp November 30, 2006
 
2.
n.: the opposite of a "bubble butt," the square butt is most often found on nappy white chicks. When using the square butt for sexual satisfaction, it is advised that a pillow, or some other cushioning device be placed between the wee-nis and the square butt to prevent bruising the male reproductive organs.
"Man, I hooked up with this square butt chick last night for two hours!"

"Are you shitting me? You wouldn't be walking if you did..."

"Look...here are the bruises to prove it!"
by Dr. Josephus October 23, 2008
 
3.
An abnormally shaped rear, somewhat ressembling a square
"Damn Pat... look at the girl with the square butt!"
by James Huge January 15, 2004