There is a great degree of variation among practicioners of this.

Often, if you see the same gal a few times, and she feels comfortable with you, you could get to have her undress and be able to touch her, even feel her up.

You need to be very discreet and non-threatening to advance to other things, and yes, sometimes even FS will be on the menu (But that is rare.)

Say something like:  "Do you ever consider offering more services to genererous men?"  If you get a smile or a nod, then take it from there.

If on the other hand, she shakes her head, then just drop it and look elsewhere next time if you want to go further with someone.

I saw a massage provider for several years before I got up the gumption to ask her for more.  Her response was:  "I don't do things like that......here."  So we started to see each other in hotel rooms and to this day we still fuck our brains out.  Oh, if only I had gotten the nerve a bit earlier.

Once again, research is the key.  Massage quality varies but some are very good.  A "Happy Ending" (HJ) is standard.  She'll probably have strayed during the massage.  Generally she will allow some touching though a cute young thing at an AMP was allowed minimal touching and took no clothing off.  (The door fee goes to the house, the massage fee paid to the girl probably gets split.)  In the end this AMP cost more than a FS independant provider.  I met with one well reviewed FBSM practioner who unbuttoned to allow touching but the bra stayed on.  I find these are rather the exception with most topless & allowing & even encouraging some touching.  Touching encourages you to get excited which helps with the conclusion.  I enjoy this experience & will move my arms & legs to the edge of the table to get at least a bit of contact as she works.
Others may be open to more activity, once they get to know you.  You should not expect a FBSM provider to offer FS for the cost of FBSM.  One Fav lady...  I still see her...  let me know more was available, clearly expected an additional fee or tip but would not specify a number (perhaps feeling that would make her vulnerable to being stung).  I decided to add to the donation to equal what I would have paid any other provider.  (I suppose a cheapskate might have trouble booking her again.  I continue to see her.)  
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