egg on / all over one's face

What is the origin of the idiom "egg on one's face" and when to use it?

The origin of the idiom "egg on one's face" can be traced back to the world of entertainment, specifically vaudeville and slapstick comedy routines. In these performances, it was common for actors or comedians to engage in humorous or exaggerated mishaps that would result in them having eggs thrown at them or smashed onto their faces. This act was intended to elicit laughter from the audience by portraying the character as clumsy, foolish, or deserving of ridicule. It is often employed in informal settings, such as social interactions, personal blunders, or professional mishaps. This expression is commonly used when someone's mistakes or errors become widely known or visible, causing them to appear foolish, incompetent, or deserving of ridicule.