I've been buying your clips since Amber came out. I'm a big fan.
My own suggestions:
1) No brushes. I agree with the guys above. It's just not as sexy as fingers.
2) Your BEST videos -- anything with Amber or Roxy -- are fabulous because of the women's personalities . They talk to you. They interact. I don't know how it is possible to find a girl that is ticklish and that has the amazing charisma of those two. But if you find one, keep bringing her back for more. And if I were you, I would ask Roxy out.
I don't just think you've been lucky. I think there is something you do that puts these women at ease. And it works.
3) Keep changing up the bondage positions, camera angles. Some really great, established producers seem to have a formula of how to tie up their ticklees (first an interview on a couch, then into the stocks, etc). And usually it is really hot, but variety is the spice of life. (I may not know what I'm talking about for #3.)
4) If Christina Carter ever offers to tickle you again, say "yes".
Really love your work. Thank you. You have made this community richer and more exciting.