some tip up front, some at the end, some not at all
some in the envelope, some outside the envelope; some don't even believe in envelopes
some tip gift cards, some chocolates, some $20 bills, some $100 bills
some tip for exceptional service; some always tip; some never tip
... so it all depends on what your style is, my dear!! 
I tip housekeepers, front desk employees who help me get the room I want, bellmen, street vendors, starbucks staff...I give to the homeless, too. It costs me very little to make someone else feel especially appreciated.
I believe in tipping.
I find it difficult to watch my date under tip a server and will usually sneak a little extra onto the table if I can without embarrassing my date. I don't understand bad tippers. Who (among hobbyists and providers) will miss a few extra dollars to make a tip or gift extra special?
I especially think a tip is in order for clients who need extra time arranging the session...whether they are trying to design the perfect role play, choose a hot outfit for me to wear, invite a third person to join us, or just enjoy extra communication pre-appointment.
My best tip was 1000$ for a 2H appointment. I've also received plenty of 100 $ tips and everything in between. It's a thrill every time, even when I get 20, 40, or 60. I feel happy for me, and I feel good about the tipper. If you want to be REMEMBERED as a generous tipper, 50$ is okay, but 100 is better. However, even throwing an extra 20 (you won't even miss it!) says, "Thanks" in a way that words just can't!
