Just walk away from them or tell someone. If it is on the Internet then you can most likely block them. Don't let them continue no matter what, and if it is your friend then tell them how it makes you feel.
Well you could say "I'm rubber you're glue, bounces off me and sticks to you" or the ever effective "I know you are but what am I?" When she tells you your acting like a baby for saying that just tell her that you were just trying to live up to her expectations. Then laugh at her and walk out of the room....
My friend used to do that all the time Goody and two weeks ago I snapped.I have been telling him to stop for over a year and nothing.So when he called two weeks ago and said on the phone hey baby..I just replied"there is no one by the name of baby here"and hung up on him.He hasn't called me baby since.
Usually if someone thinks they're not hurting you, they'll stop. Just say, "Okay, whatever, you're getting kind of annoying." Doesn't sound like a good friend, keeps on calling you names, more like a bully! Just ignore her and tell her this is enough, if you wanna keep our friendship I'd suggest you stop.