by wullie macd July 24, 2006

by SharpTheDemon December 30, 2015

by shareski November 13, 2011

by Kingdong August 30, 2006

A demand to be a man and to stop acting craven or cowardly. A derivation of man up (which in itself is a derivation of cowboy up), although more insulting. While man up can be used as encouragement to do something, sack up is almost always a challenge to cease doing something that should be beneath you
"Oh sweet mother of god! The terrorists are going to blow us up with Snapple bottles!" _This_ is terrorism's A-game? Sack up, people.
by Quine August 13, 2006

When getting into your bed at night and realize your child has decided to hide in the form of a sack of potatoes.
by Jinxie Dee Breece October 18, 2020

When your turd hits the back of your nut sack its like the two things guys pride them selves on most high five each other. Thats a sack slapper!
by Handyandy12345 January 20, 2009
