A shower taken for the specific purpose of cleaning one's butt after defecating. Usually a 30 second to 1 minute ordeal, a butt shower typically only involves cleaning one's butt using a removeable showerhead or, in some cases, hands. A butt shower can sometimes evolve into a regular shower. Often used by bidet owners when traveling to a place where they will not have a bidet (i.e. a hotel or AirBNB.)
Ludwig: I took two showers that day; the second one was just for my butthole.
Anthony: Oh, I love a butt shower.
Aiden: That's what I was doing in Australia!
Nick: Dude, I've butt showered on every trip I've gone on.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi