I research the girl and find out who is asking for the info.  Anyone can email and say, "Hi, I'm XYZ.  Have you seen ____?". So for his protection and mine, I verify that she's a legitimate escort.

Then I may tell her a brief physical description (sometimes guys pretend to be someone else/ use their friend's references to see a girl.) So maybe race, age, hair color, height, etc).

From there, just a general run through of any problems such as bad hygiene, asking for BBFS, annoying behavior (calls too much, cancels frequently, etc)

If there are no problems, I'd say just that.  No problems.  Or if I really like him, I'd say he's awesome, or ideal client, or something like that.

Usually, guys are not a problem.  And if they were, it's unlikely that they'd use me as a reference.

I don't typically give any personal/sexual info unless it's something really relevant.  Like if he is abnormally well endowed, I just discreetly tell her to bring a certain type of condom.  Or if he has unusual fetishes, I may mention that briefly.  We do NOT talk about how you are in bed.  The main concern is if you are safe, nice client or not.

I don't ask for anything specific.  Rather I check to make sure SHE is a provider, email or call her, identify myself and tell her I am asking for a reference.  I usually say I want to confirm that he is who he says he is.  She confirms or denies and that's it.  Usually it's followed up with "he is great, really sweet, gentleman, etc"

There was one time I called another provider and she could not verify my client.  When I notified my client that I could not screen him and asked for another reference he gave me 2 more.  Neither could be reached and time was running out.  Supposedly he then called the inital provider and "talked" to her and said he "got her to remember me" and that she would be contacting me to clear him.

Needless to say, I did not see that client for several different reasons.  It's a really good idea to let the provider know if you are going to use her as a reference, even if it's only a quick email to say hey, you will be hearing from someone in Maryland.

I have never been asked any specific details. Its always general and just how is he and was he a good client.  But even I somebody asked me something like that, I would NEVER give any details or any personal info a guy has told me.