In the US it *usually* means no penetration at all (i.e., not even a BJ) but lots of other erotic stimulation, including HJs, Russian or whatever to completion. For some reason it became a fairly common form of p4p in the US, especially around the DC area, a decade or more back, usually offered by women who were significantly better looking than a typical escort (at least in their own opinions!). My impression is that it is quite a bit less common these days, though I'm not sure of that. I don't recall ever trying it, but I'd think it could be quite nice if done with style and skill.
But in any case, wouldn't it be easier and more reliable to ask her for some details of her services?
-Ww