Its just a silly way to end a silly conversation.
Have you ever found yourself speaking with someone with whom you wish to end a conversation? As often as not, this person insists on pressing a point that is boorish and inconsequential.
One could answer "whatever turns you on" or "whatever floats your boat".
Most of the time nowadays, these conversation enders can be shortened to "whatever", or, when in California, "whatever dude".