Seems like the phrase in itself is quite self explanatory, but for those who miss the purpose; 'whatever floats your scrote' is a way of expressing nonchalance or easy-going-ness toward as subject or matter. If someone asks you to make a decision, this phrase can be used to suggest that they choose instead, and that you are happy to go with either option.
by Snail Cuddles June 25, 2017