Simultaneously having vaginal and anal sexual intercourse with a woman who is menstruating. The anal blood can be either from vaginal transfer or rectal bleeding.
Dude, you should see my sheets. The chick I picked up last night turned into a double blood bang!
The bloody aftermath left after having intercourse when a woman is at the apex of menstruation.
You should check out the crotch crime scene I left over at Becca's last night!