~verb~; using your testosterone flooded man jewels to take charge and become a leader, to become aggressive, or to be brave
Steve tells the team, which is plagued with a slumpish game at the bat, for it to sac up and hit the ball.
by Baron and Bondell June 13, 2004
1 more definition
~verb~ to gather all of ones bravety and ability to fight and to go after what you want.
John, seeing that steve was cryin in the corner, told steve to sac up and go ask the girl out again.
by Jacob S. April 03, 2005