I don't think it's a sh@t test. How did she ask? Of course you don't want her to tell you what to do or order you around, so tease her playfully a little first.
ZoomsChick: Hon, I wanna have some umm phone fun.
Zoom: We COULD.... If you're a good girl.
ZoomsChick: I'll be good.
Zoom: You better. Don't make me come over there lol.
ZoomsChick: mmm
Then go for it and use it as an opportunity to turn her on even more. Done properly, she will be begging you to come over.
Is it possible for her to engage in several phone s@x sessions and not put out? I've never had that happen, but I would still be careful of that. Worst case if that happens, get her really hot over the phone and close to orgasm. Suggest that you come over. If she says no, be polite and say "That's ok. I have to get going anyway. Talk to you later.". Then hang up.
Your phone will probably ring shortly due to her girlie blue b&lls lol.