Chatty, I think I would move into the questioning slowly and subtly. Maybe put them at ease with impersonal questions about how they found out about your service, about their wife and children. Their age and profession. If they are married and how long. Then ask them specifics as to what they want from the conversation (i.e. sexual release, emotional touch, lustful adventure, fettish, kinky stuff? Maybe what other types of sex they engage in and how often and when and how it started along with other things you might want to know.
Then continue with some other conversation.
Then maybe how anonymous sex differs from sex in person.
Maybe why they are seeking anonymous sex instead of having it with their wives?
Though it might be fun to know what they would think if it were their wives doing what they are doing, it would probably put them on the defensive and lose their cooperation and them as a repeat customer Though you might be able to do it if you used a sweet voice.

Chatty, if you developed a well documented survey of that type, even if you didn't write a book, it might be saleable to phone sex companies as marketing data and/or as a psychological study.
Seems like information that might be helpful to parents as well as spouses as we contend with this electronic onslaught of sexuality.
smile