1) The practice of doing bumpfire or bumpfiring a semi-automatic rifle by needlessly, inefficiently and probably unsafely having a buddy stand behind you and pull the stock of your slinged rifle. 2) Any needless, inefficient and unsafe variation on standard shooting protocol usually thought up by two (almost always male) friends when they have more ammo than targets or good sense. See, Kentucky Windage.
Hey, why is that guy using himself as a bipod for his buddy's AR?
Hmm...That right there, son, is some serious Kentucky Bumpfire.