This may not work for everyone but I usually start by asking them about their choice of profession, and also why I use them. Often times, this breaks the ice and makes us both real to each other. Then, other topics usually develop from that (hobbies, future plans, kids, etc.) I learned a long time ago that the way to a woman's heart is to L-I-S-T-E-N.

If you hit it off good conversation wise with your provider, you may turn a one or two hour session into an all nighter, but not at that price. Just talk about stuff that she has an interest in, travel for example has worked well for me, especially if she is a foreigner and you have happened to travel that country.

Instead of the topics I (or someone else) enjoy discussing, how about topics you enjoy discussing. Find out if that someone has similar interests. If you've got nothing in common, an overnight could be a long ordeal, indead. She's a human being, after all. Find some common ground and you should be in good shape.

Regarding off-limit subjects, just use common sense (and don't ask anything to which you _really_ don't want to know the answer).

Personally, there are a couple of ladies whose company I enjoy for extended recreation. I enjoy them as much for their conversation as for their skills in other endeavours. We discuss art, travel destinations, current events, aspects of our personal lives, etc. I enjoy getting to know them as people, and they seem to enjoy learning more about me.