To create a whistling noise like that of blowing over a bottle, except using another person's shit hole. Thus a shit whistler. Can be used to imply someone is of a homosexual persuasion.
Mike in a childish voice up the stairs: "I've just turned all the items in your room upside down..."
James runs to his room...
James: "Ahh mannn! You dirty little shit whistler!!"
A Shit Whistler is a person who tell complicated and incredulous lies that they alone believe. The act of doing so is referred to as "playing the shit whistle".
John's a real shit whistler...Last night he told us about how he crawled out on the wing of a flying airplane to fix the engine.