The loosening of the anus after a girl has copious amounts of anal sex.
I went home with that skank from the club and when I stuck it in her ass, I found out she had a total mush tush!
by MistahBradshaw August 30, 2010
A very soft (mushy) bowel movement in which an individual wipes their anus over and over again without any great success, resulting in an itchy butt, and the use of a whole roll of toilet paper.
Dude! Why is it that you always get mush tush at my house?! You owe me some Charmin you stinky bastard!
by Lizzyloooo November 18, 2014