Civil Barrister, you were right on the money... I have asked providers if they provide full service (gently, I might add, and without pressure), and if they reply with a $$ quote, then the red flags go up. I tip according to the service I receive, and I tip well. If you say yes to full service and don't ask for a certain $$ amount, then expect a good tip, especially if you're the least bit enthusiastic. I may not be the greatest lover in the world, but ladies, you should be acting as if I am. If you offer fetishes, then ding, ding, ding! Big tips.
Jaida, don't think that all of us are cheap or perverts. If I ask, and you say no, then it's just a rub-n-tug, and nothing more and the tip will reflect it.