Receiving a Blumpkin while taking an Upper-Decker, it's as simple as that.
Joanie loves Chachi so much that she gave him a Blumperdecker the other day in a rundown truck stop bathroom because they had nothing better to do.
Getting a blowjob while performing an upper decker
Did you here about slut last night giving him a blumper decker?
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.
Yo man, I met this girl at this doucher's house and took her in the bathroom and got into an amazing Blumper Decker. That girl gives a great hummer and that doucher's bathroom is gonna smell like shit for weeks!