When your ballsack is saggy and you stick it in her vagina when she's about to give birth so the baby starts kicking and punching at it like a punching bag from the uterus.
Right before my wife was about to give birth to my son, I performed the punching bag and he was already like manny pacquiao
by Robindaasian October 2, 2018
Get the Punching bagmug. by Zachaotic June 13, 2011
Get the Punching the turtlemug. by MayFirst83 December 7, 2016
Get the owl punchmug. by sirdigbyvelvet February 5, 2012
Get the diamond punchmug. by elinie June 29, 2011
Get the Peach Punchmug. by neil donaghy November 15, 2003
Get the punching the cloudmug. by Morsli June 5, 2009
Get the Stupid Punchmug.