Es sólo un decir.

It is just a figure of speech.

"You usually use the figure of speech "break a leg" to wish actors good luck."
Cambridge Dictionary Online

In Modern Literature:

“If you ever touch my coffee, I’ll see to it that you’re sent to the mail room to lick stamps.”
 “We have an automated licker. Do they lick stamps on Wall Street?”
 “It was a figure of speech.”
The Firm by John Grisham.

In Cartoons:

KING FEATURES