Definition & Meaning of "ass munch"in English

What is the origin of the term "ass munch" and how is it used?

Ass munch is a slang term that appeared in mid–late 20th-century English, primarily in crude, gay, or prison-related subcultures, to describe a person performing oral sex on another's anus. The term combines "ass" (anus) with "munch," implying active oral action, creating a deliberately vulgar and insulting image. Historically, it was derogatory, often used to mock, shame, or provoke, and it carries strong sexualized contempt. Today, it remains highly offensive and vulgar, and using it outside informal, sexualized, or subcultural contexts is likely to shock or insult.