It is a preperation for launching small boats from a ship. It may be lifeboats, invasion landing craft or the Captain gig. It is a warning to the ship's crew that small boats have been swung outboard and extra caution should be observed.
Whatever floats your boat means whatever works successfully for you, or whatever makes you happy. Usually the speaker uses this idiomatic expression when he isn't really interested in your comment,...
The act of pushing one's face in between two ample breasts, and rocking one's head side to side very rapidly while making a vigorous, lip-vibrating "brrr" sound.