Unbanging is the required act that must be completed to repent for "banging" or having sex with your friend's mom. In order to make up for having sex with your friend's mom, your friend must bang your mom; an unbang.
Mack banged Dennis' mom, now she will be unbanged by Dennis banging Mack's mom; and all transgressions will be forgiven.
by AlwaysSunnyInTheBasement January 11, 2010