Define Upper Decker Meaning

Upper Decker
The act of defecating in the upper tank of the toilet. When the next poor unsuspecting person flushes the toilet they get a bowl of beef stew. the upper decker is a weapon of terror and should only be used on people who deserve it.

My friends x-girl friend had a party and she left whith some other dude who looked like the fonz "Heyyy!". So I took it upon myself to leave her an upper decker
By Nola
Upper Decker
While at a respected friends house retire to their restroom, stealthily remove the lid from the back tank of their toilet and steady your cheeks directly above it. Begin defecating while trying to keep as quiet as possible. When finished, wipe all remaining fecal spatter from your anus and hide the used toilet paper in the cabinet under said friends bathroom sink. When the toilet is flushed by the next user the bowl will be rinsed with your feces. A firm stool will cause repeated minor fecal rinsing, while viscous, soupy stool will flush out all at once filling the toilet thus causing repeat flushing until clean water is present.

The upper decker was rejoiced by all who were present.
By Adelind
Upper Decker
Also referred to as 'Going Up Top,' the act of taking a shit in the tank of a toilet. Common courtesy not to flush. Used TP should be placed inside drawers, magazines, or the tank itself. Feel free to throw in any other items you can find in the bathroom during the process.

"Man this party sucks... I'll let 'em know how I feel with an Upper Decker"

"Dude!! You shit in my toilet" -> "Where else did you want me to go?" -> "Not in the top part you fuck!!"
By Ingunna
Upper Decker
The act of defecating into the upper tank of a domestic toilet.

When they started playing charades, I took an upper decker and made a quick exit.
By Dora
Upper Decker
the act of sneaking into a bathroom, quietly lifting the lid off of the toilet tank, taking a deuce in the tank and then replacing the lid. this causes the toilet water in the bowl to be polluted after each flush. this is usually done at a party or too someone that you despise.

heath snuck into the frat house bathroom and left an upper decker in the tank, much to the dismay of the alpha betas.
By Krystyna
Upper Decker
To take a crap in the tank of someone's toilet and not flush afterwards. When the next person flushes your crap comes rushing into the bowl all broken apart. A lot will clog in the top. This is mean.

It was my last day of work, and a friday to boot...so I left an upper-decker in the men's room.
By Dorri
Upper Decker
To take a crap in the top section of one's toilet so that when it is flushed, poo water flows back into the bowl.

Every a-hole deserves an upper decker!
By Vina
Upper Decker
The act of removing the upper lid to a home toilet. leaving an imense amount of defacation inside. the next customer will go and then flush your shit into the bowl, repeatedly.

while in ohio, the clarion hotel wouldnt give us a room because we werent 21, so ryan anson gave them an upper decker
By Annecorinne
Upper Decker
The act of removing the lid off the back part of a toilet and pooping in it. Poop comes in the bowl over time after flushes. Usually done at big parties that have gone wrong.

The host of that party was so horrible that Andre couldn't resist pulling an upper decker before we left.
By Aloise
Upper Decker
the act of deficating in the water tank of someones restroom, so when they flush, out comes muddy madness

i just left an upper decker in that starbucks bathroom!
By Viviyan