Hello,
First off i want to say that I personalty dislike this effect. I find the method can be quite obvious to spectators. That being said, here are my thoughts on how you could improve your performance.
1. Try to think of your own patter: the patter that Daniel Garcia teaches with the DVD only works (in my opinion) for a super relaxed performance style.
2. Try to make the rubbing action smoother. Try using small circular movements as opposed to linear movements.
That's it. I hope this helps.
Galen-