When a penis is first inserted into a bloody, menstruating vagina, and then into a butt hole, leaving it covered in blood and feces (so that said penis resembles a recently unearthed bloodworm). Usually ending with someone "taking the bait" or licking the dirty penis clean.
Dude #1 "Hey, I wanna put some p in the v
tonight but Sally is on the rag
Dude #2 "You should give her a Mississippi Blood Worm! I'll take the bait!"