What does this mean when guys are talking about a girl?

[south of here]

I was looking at this guys twitter, who I am talking to, and I saw that one of his friends replied "You're going to owe me a bill if you don't pull your future gf soon, smh"

What's that supposed to mean?? BTW..the person who said it was a girl friend of his, not a guy. So obviously he's talking to his friends about me, and his lady friends. I just don't know what in the world that means! lol

**BTW, we're not dating...we're just friends, but we both know we like eachother..he just hasn't made a move -__-

[pelican]

I think it is a disrespectful slang term for getting her into bed, for having sex with her.