a term used to describe a piece of crap floating in the bathtub
John: Dude, she just made a u-boat!

synonyms: submarine , floatin' mocha , hershey , baby bauble , "accident"
by Peter Hirsch May 22, 2007
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A lady's undercarriage - from vagina all the way under to buttocks.
Hannah, are you wearing a onesie?' - 'Hell yeah, dawg. It covers my whole U-boat.
by fujibo September 3, 2010
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(British smoking slang) When you're chilling back with your homeboys smoking up a phat joint, sometimes one will note that one side of the "bifta" burns faster than the other, and will sometimes curl upwards. When this occurs, the joint is said to be a U-boat. This usually happens because of a poorly rolled, uneven joint, or because of excess saliva on the gum side if it has just been rolled. Some synonyms for "U-boating" are "elvising" (in reference to the famous quiffed hairstyle)and "sideying" ( as it is only burnt on one side.)
"What wanker rolled this fucking joint? It's u-boating like a bitch!"

or

"That was a total waste of draw, we only smoked half of it 'cos it sideyed!"
by MikeTheBritishCunt May 4, 2006
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German submarine sandwich. Consists of German salami, onions, sauerkraut, pickles, pickled herring, and german mustard (senf), piled onto a loaf of light rye bread.
Hedley had a choice to make. Did he want the regular Italian sub or did he want to risk the U-boat Butterbrot, which like its submarine namesake held the smell of danger about it.
by steeplejack November 4, 2010
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When a dude decorates his dick as a German U-31 class u-boat, and inserts a projectile, such as a nerf dart, into his urethra, so that when he climaxes into his partner, the projectile will be launched into his choice of holes.
I’m searching for a partner to perform the Urethral U-Boat on.
by VyXious January 12, 2018
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The act of having a dump whilst in the bath.
I was having a nice soak last night, and accidently curled out a Dirty U Boat! It stank!
by Ed the Jeb June 7, 2011
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'Ramming the U-boat' refers to the act of DP of a young lady with two gentleman's parts in the same nether orifice - whether that be Dv or DA. Once one gentleman's part has been inserted, the second gentleman can be said to be 'ramming the U-boat' as he introduces his equipment alongside the first gentleman's parts - a process which will necessitate two two penii contacting each other repeatedly. The adult actress Gauge can often be seen in her films as the hostess to such an action.

While the act of 'ramming the U-boat' does involve penis-to-penis contact between two men, it's widely accepted to be only gay if the balls touch.
In this film, everything happens: DP, A2M, ramming the U-boat....
by Uncle Whippity May 10, 2007
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