Best Provider Experience

What is the best provider experience you've ever had and why?

I am not asking who was the prettiest or sexiest. I am wondering you left you thinking, 'Man, I can't wait to hit that again'. What made is so special? Was it what she was open to, the number of times, her eagerness, her patience, her oral skills, the thing she did with the ping pong balls, toys? What made her so memorable?

Feel free to give her name (or not) and location (city, state, country).