K.P.
It's from Family Guy. I only know this b/c my husband loves the show and when my son yells for me from the other room my husband will launch into it.
The little baby (Stewie) comes into his parents room and they are sleeping and he starts in with Mom, Mom, Mom, Mommy, mommy mama it goes on for a while... and she finally says WHAT??- he says "Hi" and runs out of the room.