What is "sh-h-h-h-h-h"

Sh-h-h-h-h-h is a 1955 cartoon directed by Tex Avery and produced by Walter Lantz. It was the fourth (and last) cartoon directed by Tex Avery at the Walter Lantz Studio. This cartoon features the 1922 Okeh Laughing Record for much of its soundtrack. This was the last cartoon Avery ever made, thus ending his career in theatrical animation.