A turd that is submerged in the U-bend of the toilet like the german submarines (U-boats) used to hide beneath the surface of the sea. 9 out of 10 U-bend U-boats are unflushable in the average toilet.
For fucks sake, that U-bend U-boat just won't flush! Pass me the bog brush Dave, it turd bustin' time!
by MSN NINJA April 19, 2009
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To preform a u-turn in a car/truck/van very poorly. A half handbrake turn, a 3 or more point turn or to hit something while turning around.
"I just gotta buck a u-boat over there and we're good."

"That was brutal, way to buck a u-boat buddy."
by StonedPimpSO February 25, 2009
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When you go down on your girl for so long, that your glasses get fogged up.
I went down on Marci for 54 minutes last night and I looked like a Japanese U-boat captain
by jcracky April 23, 2013
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