Wiktionary
yo momma
n. (cx AAVE English) (alternative form of your mother English)
Wikipedia
Yo Momma
Yo Momma is an American television show based upon insulting one's mother. Creators, executive producers and hosts are Wilmer Valderrama, along with Sam Sarpong (Seasons 1 and 2), Jason Everhart and Destiny Lightsy. The show—which ran from 2006 to 2007, and as the title suggests—used "yo momma" jokes, and many episodes featured guest appearances from rappers.
Usage examples of "yo momma".
Well, yo momma so ugly she stuck her head out a car window and got arrested for mooning.
Let us not forget that I was getting into trouble even worse than yours, years before you came out of yo momma, squealin an pukin, which makes me dumber than you, earlier than you.