Upper-decker Double Blumpkin 

A dude sits atop the toilet tank and craps in it, facing forward. A woman (or man, I guess...) sits on the toilet backwards and also crals as s/he performs oral sex on the guy seated atop the tank.

What were you two doing in the bathroom so long?
I expelled every fluid imaginable thanks to getting an upper-decker double blumpkin.

Upper-decker Double Blumpkin by Terry O'Raynis April 4, 2023

upper decker double deluxe blumpkin 

It's the act of the man taking a dump in the tank of the toilet while the woman takes a dump in the bowl while giving the man a blowjob while a third party performs a golden shower.

Dude, last night Stacey and Dave and I did the upper decker double deluxe Blumpkin, it was gnarly!

upper decker double deluxe blumpkin by Reedski March 27, 2015

Double Upper Decker Double Reverse Blumpkin 

The unspoken act of a female performing an upper decker, whilst a male counterpart carries out a defecation in the lower (relative to aforementioned upper deck) deck, whilst eating out the aforementioned female.

Gary and Bruce were both really excited to partake in the sensual act of a Double Upper Decker Double Reverse Blumpkin, but neither one had eaten a large enough meal to carry out the act.

Double Upper Decker Double Reverse Blumpkin by doubleupperdeckerdoublereverse October 13, 2019

Upper Decker Reverse Blumpkin Double Dump Out

Taking a dump in the toilet tank while having your dong slobbed by someone sitting reverse on the toilet while they are dumping

Me and my girlfriend totally did a upper decker reverse blumpkin double dump out!

Upper Decker Reverse Blumpkin Double Dump Out by Dick Head Buckaroo September 20, 2015

upside down double reverse blumpkin supreme 

This is when a girl is giving you dome whilst doing an upper decker in your parents bathroom while they are asleep.

Yo cindy gave me a upside down double reverse blumpkin supreme in my parnets bathroom while they were asleep

upside down double reverse blumpkin supreme by ROBE to the RT December 21, 2005

Double reverse blumpkin 

When a person is upper decking a toilet and another person is shitting backwards on said toilet giving oral sex to the person doing the upper decking.

The only reason I like house parties is pulling the old double reverse blumpkin before I leave.

Double reverse blumpkin by Coltnasty August 19, 2021

Double Decker Blumpkin 

the act of a male individual shitting or pooping in the upper deck of the toilet while a girl goes down on you (aka; sucking your penis), while she releases poop out of her butthole into the lower deck bowl of the toilet.

Jeff to Randy: Dude, bro, Jerry definitely just got some of that double decker blumpkin action dome piece from that random B with the STDs.
Randy to Jeff: Real nice, real fuckin' nice.

Double Decker Blumpkin by Lambeaux + Jerry March 27, 2009