2. The principle part of a "Yo Mama" joke, usually entailing a description of your mother being so "something" that "something" occurred as a result.
Gwen: Yeah, well so's YO MAMA!
2. "Yo mama so fat, the last time she saw 90210 was on a scale!"
"Yo mama so dumb, she thought a quarterback was a refund."
Some guy: Get a life...
Person responding: Yo mama!
Some guy: What did you say! *beats up person responding
Some guy: You fat pig...
person responding: Yo mama's a fat pig!
2) A lame phrase someone I know keeps saying whenever I ask him a question about PE because he has it before me.
2) Me: Hey, what are we doing in Pe today?
Him: Yo Mama!
Me: Shut the f up.