Comes from the term "man in the boat" referring to the clitoris and the female genitalia. So, if your boat is floating, you are quite happy.
2: That sounds nasty, but hey, whatever floats your boat.
e.g. Statement 'I prefer boys to girls'; Response 'I just like girls but whatever floats your boat is fine with me'.
thats what floats my boat at least.
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...
Chad:Whatever floats your boat.
Chad:no, asshat.its an expression.