Quote:
...Rebeca and I have always had somewhat of a strange relationship since both her and I have cheated on our boy/girlfriends with each other. We still occasionally sleep together...
Stop.
Right there, you should know that this girl is probably not a safe pivot. If you're going to use a girl to pick up other women, it ideally will be someone who has
zero chance of getting jealous and cockblocking you (which is what it sounds like happened in your case).
Try a cousin, sister, or a friend's girlfriend.
If what you're doing is trying to get with Rebecca, you're on the right track. However, the title of your post is "Girl Wingman" so I assume that this is not the case.
My most effective use of pivots has been for the first 2-5 minutes after opening. Just let them assume that you're a couple, and get them to let their guard down until they've decided to like you. After I have generated comfort and rapport, I usually tell a story about my pivot's boyfriend to clarify that I'm single.