The phrase “you don’t have to twist my arm” is a way of saying that you are eager or willing to do something, without needing much persuasion or coercion. It is often used in a humorous or sarcastic tone, to imply that the thing you are agreeing to do is something you enjoy or benefit from. For example, if someone offers you a piece of cake, you might say “you don’t have to twist my arm” to show that you are happy to accept it.
The phrase comes from the idiom “to twist someone’s arm”, which means to pressure or force someone to do something they do not want to do. The image is of physically hurting someone until they agree to cooperate. For example, if someone says “I had to twist his arm to get him to join the project”, it means they had to use a lot of influence or arguments to convince him.
