A warning that one should stop listening (perhaps by covering one's ears, in the manner of actual earmuffs).

Where does the term earmuffs come from?

also earmuff, "one of a pair of adjustable soft coverings for the ear, secured in place by a wire or spring, worn as a protection against the cold," 1859, from ear (n.

How do you use earmuff?

Hold the earplug between your thumb and forefinger. Roll and compress the entire earplug to a small, crease-free cylinder. While still rolling, use your other hand to reach over your head and pull up on your outer ear. This straightens the ear canal, making way for a snug fit.