Baggy, once she does it, even once in some tiny way...she will soon literally LOVE IT and be all over you with sexual displays, flirting, etc.
She just hasn't experienced it yet so she has no idea how rewarding it is to feel like a WOMAN. The power of WOMAN is intoxicating, even to ourselves!
Just a question though, haven't you taken my advice yet and told her straight up to flash you? Just getting her to do this, via an act of masculine selfish demand upon her by you, will turn her on and give her a taste of what it might feel like to actually do it on her own initiative.
