Whatever floats your boat is a colloquial expression, used for deferring the preferences of others.
It roughly translates to “whatever you like” or “whatever your preference is”.
The phrase developed from the modified version of phrases like “whatever suits you” which started appearing during the 19th century, with an early example for “whatever gives you pleasure” coming from 1826.
By the 1970’s, variations like “whatever turns you on” also appeared in English.
“Whatever floats your boat” would first show up in the early 1980’s, with the first documented examples coming from magazines and newspaper articles.
Over the years, the expression turned into an idiomatic phrase, used and recognized all across the Anglosphere.
“Whatever floats your boat” was first defined on Urban Dictionary in 2004.