dirty treehouse Share definition Flag word used to refer to when a girl shits on a guy's dick during anal sex. guy 1: "sooo how did your date go last night?" guy 2: "dirty treehouse." guy 1: "ewwwwww!" dirty treehouse by fencingbandodewman13 November 19, 2010 0 0 Get merch Get the dirty treehouse mug. Buy Now — $32.95 See more merch