GFE is an agent to set a date for you and the girl you choose on her pictures or profile and pay for.
The rest is up to you. You can have a relationship　or be just lovers. But I assume quite a few of them are not licensed.
Legally licensed adult service is safe and secure though you cannot meet her personally.
You usually check girls' pictures and profile on their website.
You can read their blog in some escort clubs, which helps you make a decision.
And call in if you find someone you like.
After she comes, you just fill yourself at home or your hotel room. If you choose a rendezvous course, you feel like a date.
Sometimes you get a big luck, sometimes not.
Quite a few users think it is a part of fun.
By the way, commercial intercourse is illegal in Japan.
It is smart to enjoy a psuedo-love affair in a licensed adult service.