What should i do to make him ask me out and dump her?

I've known him for like 8 years and I realized like a year ago that I really like him. He is a naturally flirty person, so I could never tell if he liked me back or not. I just found out this saturday that he has a girlfriend and he only knew her for...

four hours! We're only 13 so I'ts obviously not serious and they've only been going out for a week. He always asks me to slow dance at bar mitvas and stuff, and flirts with me a lot, but like I said before he has a naturally flirty personality. What should I do to make him ask me out and dump her?

If he is asking you to dance and so on then there is definitely some type of interest. Boys don't ask girls to dance if they don't like them. Now that he has a g-friend you'll just have to play low key and respect his choice. Keep being a good friend and just be there for him if he needs to talk. G-friends come and go but truly good friends make serious relationship material. That's who you should be for him: a good friend. Be patient, usually relationships like that of your friend (together after 4 hours) don't last long. Once, he's done that, he'll be single again and up for grabs. And he is sure to remember who his good friends were when the going got tough. That's when you'll have to make your move and show him you want to be more then friends.