someone who can party all night, smoke two packs a day, drink through a 6 pack, sleep for 20 hours, and then scribble on a pad of staff paper for five minutes and call it a hard day's work.
The feeling one may get when composing a piece. It occurs when the composer, per se, feels as if their piece has already been written and is just coming from the back of their brain.
John: "Hey, Jeannette! What are you doing?"
Jeanette: "Ah, I'm composing a cello piece!"
John: "Cool, can I hear?"
Jeanette: "No, not yet. I'm afraid I have composer's paranoia! It would be embarrassing if you already knew the piece."