The combination of a blumpkin and an upper decker.
To defecate in the tank of one's toilet while receiving a blowjob.
i.e. To get mad domepiece while releasing the beast into the top of that Faggoty Ann's toilet.
Leopold: My asshole roommate fucked my mom last week, so I asked his mom to come over to 'see which of his clothes not to donate'. I broke out a decadent white zinf at the end, and one thing led to another... Next thing I know I'm getting him back with a blumper decker in his bathroom with his mom.
Lance: My stars, good play.