look up any word, like pussy:
 
1.
Putting it down. Promising.
"I'm gonna make 100 bucks today...I put that on mamas"
by KoomLauDee January 08, 2008
 
2.
To make a statement of oath. As in, "I swear on my mom"
Archie: Yo, you did not just sleep with Veronica.
Jughead: Dude, on mamas.
by Jughead Jones September 06, 2010