The mark on one side of your lover's face caused by long vigorous heterosexual sex in the missionary position. Characteristically shown by a red beard-burn on the apple of the cheek and black eye make-up that has smudged around the respective side, giving a bruising effect. The "Mark" can often times be confused as spousal abuse as it looks like the bitch just got punched in the face.
"I'm worried about your wife...do you beat her?"
"No man, thats just the Mark of the Beast."