Mississippi Mud Boat

The act of bobbing in the toilet for feces while someone is performing anal sex from behind.
This is one hell of a weird Halloween party, Mike! Did you see they're doing the Mississippi Mud Boat down by the bonfire?
by Bird Dog and T January 19, 2008
mugGet the Mississippi Mud Boatmug.
5 or more men performing anal sex in-line with each other. Extra points if it's incestuous.
Hey Tom, the guys wanna know if you're in for a Mississippi Mud Boat Ride this weekend?
by Big Ern Mccracken February 16, 2020
mugGet the Mississippi Mud Boat Ridemug.