Rather than telling a potential dating partner, friend, or business colleague anything they can use against you, throw out a red herring. If you sense a narcissist trying to poke and prod into your past to get ammunition, share a small insecurity or fear (can be real or false) and see if they use it against you as a covert put-down or as a way to detract from your self-esteem. Now you know exactly the type of person you’re dealing with.