Definition & Meaning of "assmaster"in English

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

Assmaster is a slang term that appeared in mid-20th-century English to describe a man who engages in anal sex with other men, often in an assertive or dominant role. The term combines "ass," referring to the buttocks or anal sex, with "master," emphasizing control or dominance, literally labeling someone by their sexual behavior and role. Historically, it was derogatory and sexualized, used to mock or highlight aggressive sexual behavior, and today it remains vulgar and offensive, generally limited to sexualized, informal, or subcultural contexts rather than polite or neutral conversation.