A sexual fetish or sexual move where after pooping, one does not wipe well enough and leaves poop on the butthole then gets their ass eaten
My buddy is a little weird, he asks girls to not wipe so he can get a rusty drain.
The act of urinating inside his/her anus and they stand up and let it drain on you.
Last night, Stacy gave my a rusty drain pipe.
Oh my gosh, she bent over and I saw she had a rusty drain pipe.