So if you use the search feature you'll find more than a few hours of reading on the topic.

But to give you an executive summary:

Tipping is never required, and you are free to decide if and how much based on your satisfaction.

I tip about 20%, less on a long date.

I give the tip after the session by palming it just before the goodbye hug and kiss, and folding it into her palm as our hands part.  Gals seem to like that.

Get your reading glasses.

Ugh, I didn't push back my search period far enough before posting. Now I see a lot more discussion on the topic. My bad. This is why I'm on the Newbie board.

Thanks, mrfisher, for the point about palming it to them, though. It sounds like there's no real wrong way to present the tip, which makes sense. Once you've rolled around naked together, worrying about an envelope seems a bit redundant, huh...

beyond a Happy Ending.  I started with such a lady.  Once she got to know you, extras were available.  BUT she'd never discuss what she expected.  I didn't want to disappoint, though I could have gotten off "for cheap" I also was smart enough to realize I'd not be likely to get such generous service if I was stingy.  I added enough to equal what I'd expect to gift a FS provider in my area & she contues to welcome me to her bed.  So I guess that worked out.  Her FBSM rate was just 100 so that was about half of a FS rate.  
Normally a quality FS provider gives an "all inclusive rate"...  except for side trips to Greece which is 100 clams extra if it's on the voyage at all.  
On a first visit, the donation is left in plain view.  As you depart, you can have it in your hand as you kiss her goodbye.  Or you can leave it behind where it'll be seen.

Hi Honest;
   First off, asked sincerely, there is no such thing as a stupid question on the newbie board.
  If you "frequently include more than the agreed-upon rate in the envelope" then hell yes, that's a tip. However, if I understand your method correctly, it sounds like you are tipping before any service has even been rendered. I personally would not do that, no matter what the service was. To me a tip comes afterward, for service well rendered or better yet, above and beyond the normal level of service.
  I very often tip, but not always. When I do, my mo is to leave it in the bathroom and then mention on my way out that there's a little something extra there for her. If it's someone I see on a regular basis I sometimes will tip and sometimes not depending on how things went. I've found with many "regulars" that if I always tip it seems to become expected and the service often declines some. I too will often bring a gift, mostly for ladies I've seen before. That's in addition to any tip and I personally stay away from gifts of flowers or chocolate.
  As to the amount of a tip, that's entirely up to you. Remember that it's often the thought that counts. :>)
  Lastly, those who suggested reading prior posts have given you good advice.....take it.
                                                   Regards.....RR

Strange, but that's the norm.  Even for a regular bodyrub, a 20% tip is pretty standard...more if she does extras.

For escorts, it's usually just a flat rate, and that's it.

Just give her the tip at the end of the session, and let her know something along the lines of..."Thanks so much, this is a little extra for you."

It doesn't matter what you tip, but I would use 20% as a general rule of thumb, but the lowest tip for an escort being $50.  I would rather give no tip than something too small.

We aren't kidding when we say they're not expected. Giftcards almost imply more thoughtfulness, and you'll stand out for putting thought into it. I kind of like being forced to get myself a little something. Usually it's an Amazon.com card to help fill my kindle.

(Most recently, picked up American Gods. Really enjoying it.)