When a bigger girl without much breast muscle mass puts on a too tight sports bra and it looks like she has one single breast around her chest and spilling over to the sides.
Sometimes, you see a girl walking down the street and she's all mash-patitty and then you see her gym bag and see its the sports bra.
by cinemaone February 11, 2011
The act of mashing ones titties against someone or something
My wife gave me some mashpatitties last night.
by TheBestUserNameEver May 15, 2016