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10.
(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 04, 2006
 
1.
literally "unterseeboot" or German for "Under water boat"
OK, It's a German submarine.
by IrishRepublicanArmy December 21, 2003
 
2.
this is the name of drink, mostly use in poland. put short-drink (wet) of vodka into your glass of beer and drink it all in very short time
-o man. i'm so drunk! i've drink 5 u-boat's in 20min!
by qwertyswertly December 29, 2005
 
3.
a submarine used in world war one and two
"omg the uboat is coming"
by Taylor Hewitt October 26, 2004
 
4.
A long and sturdy albeit plastic turd that bends in a U plugging the toilet when the moment off truth arrives.
Man I had to swab the deck after U-boat 7:17 left the dock.
by delmarskd! October 20, 2011
 
5.
When a man sneaks up on his girlfriend or wife while she is sleeping and puts it in her butt.
While Emma slept, Gary snuck under the covers and gave her the... u-boat.
by The Blodger October 27, 2011
 
6.
to go smoke some cigs
person A: "hey man, you wanna go Uboat?"
person B: "sure dude, i need a doog something fierce"
by sauve8392 June 12, 2009
 
7.
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 03, 2010