Mudslide canoeing 

During anal intercourse the male hits a nerve that causes the female to start shitting uncontrollably on the males dick, while the male continues to bang her using the shit as lube.

Amanda was taking it up the butt when suddenly she had the urge to shit. John then continued to bang and begin his journey of "mudslide canoeing" until he was satisfied.

Mudslide canoeing by Domweatherman February 4, 2014