a sexual act when you fuck a chick (or guy if your gay) in the ass till you cum. then when they shit you shove it in their mouth.
Person 1: Dude Dave gave Emma a Marshmallow Brownie last night!
Person 2: Really?!?!? Did she eat the whole thing?
Person 2: Really?!?!? Did she eat the whole thing?
by Goat balls? September 17, 2011
Get the Marshmallow browniemug.