"But I poop from there" is a fad regarding a porn film and anal sex. The YTMND quotes porno actress Anne Howe trying to coax an actor out of drilling her in the colon by saying "But I poop from there" The actor, Buck Adams, having no qualms about getting fecal matter on his penis simply ignores her deterrent and casually says "Not right now you don't" An imporant thing about the fad is that the "naughty parts" are censored by a "red X" normally found on webpages for images that do not load up correctly (sometimes referred to as the floating red X of doom). Most fad sites will have other images censored with a red X along with the quote.
The scene comes from the Movie "Young and Anal 15"
Girl: "But I poop from there"
Guy: "Not tonight you don't"