When you take a crap and the stools are exceptionally large.
"Man, after eating that block of cheese yesterday I really had to play Sink the Bismarck this morning"
by castufari August 28, 2007
A term describing the act of anal intercourse.
"She likes it when I sink the Bismarck". or "I'm totally sinking the Bismarck tonight!"
by BRM1975 October 25, 2013
Basically its like a Donkey punch, but rather than dropping the forarm on the back, you drop it on the bottom of the neck.
Instead of donky punching my girlfriend, i decided to sink the bismarck and she collapsed on the floor.
by baby huey9999 December 30, 2005