Like motorboating but when you boat in the swamp you encounter mud.
Where one motorboats a ladies breasts, one would swampboat her butt cheeks.
A variation of the motorboating of the breasts. This involvles sticking ones face and mouth into anothers butthole and doing the motorboat maneuver.
Last night she wanted me to motorboat her, but I told her let's do something more adventurous. Sit on my face baby, we're gonna swampboat.