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".