Whenever a guy is having sex with a woman from behind while she's on a heavy flow for her period, and takes his dick out and whips her on the back with it, leaving long red streaks across her back, much like when a member of a religious organization flogs themselves as a form of self punishment.
"Andrew was fucking Deanna hard from behind, and her period was really going strong, so he pulled his dick out and gave her the backwhipping of a lifetime".
by Evil Billionaire June 16, 2011