It ideally doesn't need to be dusted with anything, but I personally feel that, if I take mine straight out of water or anything, it will retain moisture even after a brief pat-down dry, or if I leave it alone for quite a while it may develop an oily-ness at its base (by base I mean flat-backing side) and at times leave an oil stain on whatever it was it was sitting on (i.e. paper)
Soooo, while it ideally should not need dusting, I feel as though a dusting would benefit it, yeah. (I personally have never dusted mine.) I've heard of corn starch being most popular for dusting. Once I've read of a "mixture of flour and medical powder" being used, on FTM Mall.
I sometimes worry about yeast infections, so I don't dust for that reason, although I honestly have no idea what causes yeast infections. I sometimes jut figure corn starch and flour seem yeast-y, soo...
Maybe baby powder could work also