I am in a new situation and need advice.  I am meeting a provider for a drink prior to the fun.  All good, but when is it appropriate to give her the envelope?  When we meet for drinks ... seems to public?  or when we arrive at the incall... leaving an envelope out on a table as with other providers?

Any advice?

When she asks for it usually works. She's as concerned about propriety as you are. Definitely when you're in private, though.

Some may have instructions on how the like it handled on their ad or website.  When you get back to the room, just discretely drop it off somewhere where she will clearly see it.

I've been on the receiving end of this scenario many times.  Bring a magazine or newspaper and simply tuck it in there.  I've also had gents ask about books I was interested in so they would purchase the book and leave the donation envelope in there.  Don't fret too much, it will all work out!

Cheers,
Stella