The act of forcefully smashing another person's anus with your knee, usually when they are bent over. If victim is standing, distributor of said act may grasp victim's shoulders to ensure they won't avoid a vicious Gay Rhino.
Person 1: "Dude my anus still hurts from that gay rhino the other day."
Person 2: "Haha yeah, I really dug my knee up your butt hard."
Person 2: "Haha yeah, I really dug my knee up your butt hard."
by bigoldfatguy October 09, 2011
by roboto June 10, 2007
by DaDard November 29, 2017