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.

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.

The act of defecating into the upper tank of a domestic toilet.

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 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.

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.

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.