To flirt with friends/or a friend without having the intentions of dating them, most times done when a person has nothing better to do. Sometimes this may be misinterpreted as "real" flirting. Meaning, flirting with the person because you actually liked them.
Friend 1: Did you see her and him flirting today?
Friend 2: No, she doesn't like him. She was just friend flirting with him.
Friend 1: Oh, Ok.