Page, see your advise is already flawed. You comment about "going" for the number at the end before you leave. If your "game" worked, you shouldn't even have to worry about her number because one of two options:
A.) Her jealous friend wants to leave or she just gets up WAY early and offers YOU her number.
B.) You play the "I dont really care, I pick up girls like nothing" card, get up, tell her you got to go, and she tells you that she wants to hook up agian and offers the number.
If she doesnt offer you the number, your game is worthless, cause sure, you ask her for her number, but does it mean she will pick up the next day?
In Tribute to Adam Sliger. Rest in Peace
10/7/85 - 12/9/03