Quiz: Do you know your Cockney rhyming slang?
“Loaf of Bread” means “head” or “bed”?
“Whistle and Flute” means “suit” or “boot”.
That’s not how it works at all. My knowledge of it is a bit archaic (like any slang it changes over the years) but the basic point still stands.
Loaf means head, whistle means suit.
The rhyme is unsaid. To work out what a word means you’ve got to work out what a common phrase would be which starts with that word, then look for the rhyme with the second word.
For example, we want to construct a slang word for “face”. What rhymes with face, hmm, race. What’s a common phrase that uses race in it? “Boat race”. Thus “boat” means “face”. “Apples” means “stairs” via “apples and pears” (both of those I have had used at me in real life).
To walk around asking what “whistle and flute” means is to entirely miss the point of the patois in the first place.