I feel like this a controversial topic and one that many clients and providers will differ on based on their expectations and experience.
Generally a GFE or girlfriend experience with an escort means something you would expect in terms of a fantasy encounter but with a significant other. It would be familiar, consensual, passionate/sensual/romantic, sexy and feel like a natural encounter.
Escort service has not always been that way. In fact the GFE experience was only popularized a few years ago in the New York sex scene because some men were looking for a different kind of session. Some were not turned on by a standard session that was cold or impersonal and with many providers did not include kissing or intimacy of any kind. After it became popularized a lot of escorts worldwide adopted and even preferred to offer that type of experience for clients, and some offer an option for gfe or pse (porn star experience) for wider variety.
For some clients the intimacy and natural comfort of being with a lady is something that they seek out, rather than an anonymous "one night stand" encounter that leaves them feeling a little too disconnected after it's over.
My specialty is offering a natural and unrushed girlfriend type of experience for clients - even if we've just only met. To make them feel appreciated and cared for and enjoy a natural intimate connection with them. I am greeting clients warmly, happy to see them, want to find common ground to connect on, and make them feel special while enjoying an intimate and private experience. I take my time with them, I'm not watching the clock or abruptly ending anything to rush them out either. When I am with a client my focus is on them, and them alone to build a truly memorable and unique experience that is more than just physical.
My girlfriend experience session however is not like everyone else's or all client's expectations. I once had a rather rude message from a review board member who told me he wouldn't be seeing me unless I offer a CIM (come in mouth) service because to "him" that was "TRUE GFE" (whatever that means!)
While some gents have girlfriends that have provided that kind of oral fantasy for them, and some providers are comfortable with that - I find that it is not something that is widely expected/demanded for in terms of GFE service. For myself I don't offer it and say that is part of a PSE service that I don't personally do.
I also don't like any sort of rough slapping, spanking, hair pulling, biting, choking, behaviour as well as for my type of gfe that is not something I enjoy or want to happen in a session.
Many ladies will also state that GFE is an attitude as well, so if they are comfortable with a wilder sort of intimate session they will let you know, but probably still expect that you still treat them with respect and not cross boundaries in a way that you would with a real girlfriend.
So although your experience may differ as a client in what you've done with a significant other or provider, every provider will have a slightly different comfort level and session.
This is where doing your research on a lady, (be it reading reviews or her website for more information) will help you connect better and find someone who is offering an experience that you are looking for.
Also please keep in mind the area that you are searching for a lady in. Some countries it is normal and even expected to discuss services, and in others it is illegal and deemed tacky/dangerous to discuss services. So it will depend on who you are contacting and where they are what their comfort level will be with discussing such services if at all. I live in Toronto, Canada so it is not illegal for me to offer my services, but many of the third party sites I host my ad on preclude us from mentioning any services as it's illegal to advertise on someone's elses behalf.
If you must discuss, being tactful and respectful is always the best approach. After all first impressions are often all we have to go on when considering whether to continue speaking with a client to set up an appointment.