Ladies,where exactly does she want this to go?

Totally agree with WAYWAY. You need to figure out where you stand with your present relationship before you begin taunting another girl with these massages. You are just making life too complicated for yourself and those around you. Take one step at a time. Break up, then start flirting. This sexual energy should be shared with your girlfriend, not your co-worker.

My first thought is, you both have significant others? I am not saying a man and a woman cannot be friends, or even best friends, but I do believe it is a rarity for two heterosexual people to be THAT close and not have sexual feelings for each other. I think you need to sit and think about what do YOU want from your relationship with her? Do you want to be with her? Or do you want her to just be a friend? If you want to be with her, you might want to assess your relationship with your significant other. As far as her behavior goes, I certainly would never allow my male friends to rub my back gently with their finger tips with my shirt up. I would say she definitely is attracted to you emotionally and sexually, but since she has a significant other wants to be positive that you feel the same way before she risks breaking up with the other guy. I know that seems shady, but it is what many women AND men do.kind of like monkeys swinging from one partner to the next. She definitely wants to take it further.