What do they discuss? Is it just a safety check (make sure the client is clean, polite, not too rough, etc) or do they discuss positions/other stuff the client likes/dislikes.

...I expect that some are of few words, and simply ask other ladies if the client was respectful, paid up and wasn't an axe murderer. Others probably ask a bit more, perhaps looking for the types of activities or fetishes that a client might want or other preference type info so that they will know what to expect.

The usual reference request looks something like this: "Have you seen him recently and was he okay - or - would you see him again?"  

I can only speak for myself as well.  
When I contact a provider I just say basically,

only not in these words.  she pretty much agreed, after the info that a guy is safe and clean and pays reliably, not much else is exchanged.  because, she said, you don't want to influence another person's experience.

It really depends on what the provider requesting the info asks...for the most at it is- sanity, reliability (timeliness, pays expected gift without negociation), plus any detail that my hobbiest wants me to share.  

I just want to make sure clients are safe.I ask hookers have you seen clients giving hookers has references.I don't discuss unimportant bullshit  

Quote of the day! "PS. Bring Magnums." Classic!

that should be kept between providers  
XOXOXO,
TL

rest assured they are not discussing your bedroom prowess or mocking your shortcomings.

I was told by a provider that the reference I use told her that I was not good at daty. So yes some do talk about how good or bad you are in the bedroom.

That's true... I'm solely interested in whether or not he is a gentleman, doesn't try any unsafe shenanigans, and if she herself would see him again.  I also am paranoid about LE, so I look for specific words in the Provider's response.  

Haha, trust me. I'm more or less average in the looks and cock department.

Just kidding. I've heard that some providers like to share intimate details, but I've yet to come across a reference like this. We just keep it professional and share any necessary information regarding safety and of course verify identity. Everything else is unnecessary, unprofessional often irrelevant. For instance, what you like with Xy, you may abhor with Yz.  

What we really want to know is that you are not  
1) law enforcement
2) rough or abusive verbally (unless agreed upon)
3) that you kept your appointment time
Beyond that, the rest just depends on the relationship with the provider I'm asking. If it's a friend she might say "you'll like him" because she knows me, my likes/dislikes and specialties. If I find out he's really into something that I am not, I'll refer him to someone I know who caters to that desire.

The last date I had, the lady told me she checked my references and ladies had very good things to say about me. And then she proceeded to sit on my face and tell me to eat her pussy. Wonder where she got that idea? Actually, I haven't quite figured it out but I have a good idea.