This girl always plays with me what should i do?

There's his girl she is from a diffrent school we meet at a debate tournament we started talking and hen she started flirting and making dirty jokes before we were going to debate then afterwards she would just play or tease with me she has these bright blur eyes and would just try to hypnotize me by just staring at me or she would laugh at everything I said then I found out she had a bf and evey two weeks we would have a tournament after her bf left she would flirt with me and when the bf came back she would hug him then look at me like she was teasing me then after he leaves she would sit by me rub my hair put her head on my shoulder or just talk to me she is really really hot and pretty and she has me under her spell I think she is going to break up with her bf should I ask her out or wait for her to ask me out or should I trust her I can stop thinking about her and every single tournament we seem to get closer and closer I wonder if she's a heartbreakers is she suckig me in to her twisted tornado of love what should do?