eating muff - Going down on a woman. People say it to tease or insult some

Going down on a woman. People say it to tease or insult someone, like when they call you a muff eater to make you look stupid.

My crush called me a muff eater in a group chat.

At school, my friend said, 'You’re a muff eater, and that’s not cool.'

My brother sent me a message: 'You’re a muff eater, and I’m not proud of you.'