Removing the lid of the back of someone's toilet and shitting in the clean water. Results in shit running into the boil with every flush
by Dan April 5, 2004
This one takes practice. This maneuver requires a toilet with a tank above it, like the ones in most homes. Instead of crapping in the bowl, you shit in the tank. Now don't flush. When the following victim flushes, the rancid waste fills the bowl. If you play your cards right, it may ferment. Great prank for those lame partys.
by CharlesVA August 5, 2006
Using the restroom, going number one or two in the water tank of a fellow man's toilet. when he flushes the pee or shit flows out.
by douchebagness May 3, 2007
An upperdecker is when you poop in the toilet tank of someones bathroom, its the gift that keeps on giving
by Nick June 17, 2006
by Squeegie Bandit May 22, 2008
The upperdecker is a prank that you can pull on a friend or loved one, or more likely someone who deserves it. An upperdecker is defined as defecating in the upper tank of a toilet, allowing it to fester for as long as possible and sending a chilling brown residue into the bowl upon each flush.
At a party where they run out of beer one might like to leave an "upperdecker" to show their disapproval.
by Grant Herman August 31, 2004
A vengeful act of defacating in the tank of a toilet so as to odorize the bathroom with every flush for weeks until found. This is usually done at parties where you don't like the host/hostess.
"everytime I flush the toilet my bathroom wreaks, someone must have left an upperdecker, when I said the parties over go home..OH man! they did."
by troy garner September 2, 2005