Background:
So I've been gaming this particular girl for some time now. At first, I was doing everything wrong and she was not into me at all. It was hard to even get her to meet. However, I've managed to build attraction, comfort, and have been building up a lot of sexual tension. I've used a lot of kino techniques, such as, tickling, smelling hair and etc and she has been responding quite positively to them.

Chick Type:
This girl is a wild type, very sexual, has a lot of guy friends and not really a wifey type of girl. A girl you just want to have fun with and drop later on. The thing is, I met her sister not too long ago and I'm finding myself to be much more attracted to her than the girl I'm currently gaming.

Problem:
I'm supposed to hang out with the girl I'm gaming tomorrow, and my plan was to make a move on her, but am getting second thoughts now that I've met her sister.

I know if I hook up with this girl, there's little to no chance I'll ever get with her sister. How should I play this? How am I supposed to hook up with her sister? I have her sisters PHONE NUMBER, but what do I text her? I don't want her showing her sister and it blowing up in my face. Btw, her sister shows slight IOI's (like she'll stand really close to me with our arms touching), but nothing definite. I haven't really been able to get any alone time with her to find out.

Should I just smash the girl I'm gaming and move on?? I can really see a future with her sister though.

Aha, man you're just like me.

I'm going to refer to the girl you could probably smash as girl A, her sister as girl B

Yeah this one's a bit tricky, if you show too much interest in GIRL B when you know you have a chance with the GIRL A, it could ruin everything.

You could actually show some interest in GIRL B, try to build some attraction with her, then use the GIRL A to get her jealous. Then figure out one day you think GIRL A would be busy, then invite GIRL B to something you are already doing with a couple of friends. Act like you just want to hangout, nothing more.

Once you get her to hangout make her laugh a little, build extra attraction, get her alone, kino, kiss, fuck.