Allright I had a K-Close, so had to come up with a N-Close as well of my own.
You COULD use it as an opener but then I'd adjust it. Also I had the idea like 20 min ago so I'm not sure about it how to react... so that's why I post it. The basics however are simple.
Pua: Hey, Hm I can't see my friends and I think they went to the other club. Can I use ur phone for a sec since my mate blaa has my phone...
HB: Ah sure. *gives phone*.
You ring your nr. Now you can do this in various ways.
Pua: Oh look here's my phone. Now, what's ur name again? *hand over the phone with her nr showing in the display*
Pua: Ah thanks. I'll call you on monday.
Pua: Thanks
Now walk off and later on txt her, you got her nr from your mates mobile and you thought it would be nice to hang out at some party or with whatever lame excuse. Don't tell that you want to see HER. There's an excuse to invite her over.
Pua: *in a playfull name* Ahhhaa! Got ya! And show her nr. Then say something like "Ohhh never thought you'd actually fall for this.

Hope you don't mind? Or I'll delete it right now.
Thing is you don't wanna destroy the trust you got. *if any*
SO my question to you... how to do this properly and what finishing touch would be the best for this one? Thanks in advance.

It seems like quite a bullitproof way of asking a nr close.
Edit
I'm prolly going with this one:
Okay gotta go now, he's not picking up, guess it's too loud. I prolly have your nr now, if so I give you a ring but ONLY.. *pause* if there's a cool party going on and ONLY... *another pause*.. if I get a hug now. *friendly smile*
If she hugs you it's a "yes its okay to call me".