22
When someone poops in the top part of a toilet, (the part that you have to take the top off) so when someone else goes to the bathroom and flushes the toilet instead of clean water coming in and filling the toilet, shit water comes in. This is done as a pratical joke, usually done at parties.
Guy 1:Hey I just did that Upper Decker in the toilet upstairs and Jennifer went in there.
Guy 2:Hahahah, what'd she do when she came out?
Guy 1:I don't know, she's still in there!
by Kevinnnnnnnnnn December 26, 2009
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23
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 darby krow February 03, 2010
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24
When you go in the TOP tank of the toilet. Best used at a party or with an audience.
Aw, man! Someone pulled an upper decker!
by Goldgoatturd February 20, 2009
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25
A long home run ball hit into the upper seats of a baseball stadium.
After I caught an upper decker at Busch Stadium, I went to Dan's house where I left a beefy sewer pickle in the tank of his toilet.
by porknut August 11, 2005
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26
(Film Critique). When a movie starts out engaging and has great potential, but then the ending falls apart and the whole thing turns to shit. It's like finding an Upper Decker when you flush your toilet at the end of a party. It's there, and it's shit, you just don't know it yet.
The movie Enemy (2013) was a real Upper Decker.
by Britley's Grams September 04, 2016
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27
To take a shit in the top of the toilet, therefore when the toilet is flushed, brown water washes the poop down.
"That fuckin bitch wouldn't blow me so I am going to leave her an upper decker"
by chops renfer August 22, 2006
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28
take a shit in the top of someones toilet (where all the toilet guts are)
Valerie was so drunk she did an upper decker in her friends toilet at the party, and everyone smelt it.
by valere March 13, 2008
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