This straight girl who flirts with me...I don't get her.?

Now this girl and I have had a history, she's a gorgeous straight girl who likes to experiment or liked to. She used to grind on me at parties and once we were dancing on each other and kissed each other, and the way she grabs at me when we're dancing made it seem like she was highly attracted to me. So I guess I missed the bus on that opportunity but I'm very skeptical of "straight" girls. Now we had one hot evening of which included a very hot lapdance, and kissing each other on the neck...but then she got a boyfriend. Even now she's got this boyfriend but when he's not around she flirts with me, or she'll cuddle with me unlike any cuddling she does with straight girls. She will wrap herself around me, or hold my hand, and I'm weak because I fall for it everytime. There have been really awkward moments where she will say something flirty and I'll play along and then it stops and we stare at each other embarred...and she says very suggestive things to me...but I don't know if she's toying with me or if she is genuinely attracted to me. My gut feeling is that she is but conflicted because she's in a relationship. I have always been the non-aggressor when it came to flirting with her, she'd always make the move. And she only acts like that when her boyfriend isn't around...tell me, what is she thinking?