One of my rules is never explain. A writer is a lot like a magician, if you explain how the trick works then a lot of the magic turns mundane.
“I am fully persuaded that thousands of our fellow-men might profit equally by a similar course to mine; but, constitutions not being all alike, a different course of treatment may be advisable for the removal of so tormenting an affliction.”
“Twinkle, twinkle little bat How I wonder what you're at! Up above the world you fly, Like a tea-tray in the sky.”