also used as an expression which means "you can do whatever your preference is."
i dont see how that has anything to do with water, though...
Jeremy:Hey Chad want to go to Mcdonalds or Taco Bell across the street?
Chad:Whatever floats your boat.
Jeremy:uh, water?...
Chad:no, asshat.its an expression.
guy1: hey dude that girl is smokin hawt!
guy2: nah man idk what ur smokin cuz that chik overthere is smokin hawt!
guy1: eh what ever floats your boat man...
The phrase used to confirm something when you are moderately indifferent to the actions of a friend who's mental faculties are questionable.
Person 1: So Im gonna ask Grey to marry me today.
Person 2: Didn't you just meet?
Person 1: So?
Person 2: Whatever floats your boat, tickles your pickle, pops your peach