This is where I am also different from many.....
The session is NOT satisfying for me unless the Mistress's hand is actively part of the experience of cumming, to be polite.
As a result I now see mostly European Mistresses whenever I can when travelling overseas and find that European Born Dominatrixes in the USA are most comfortable with this predilection. I know "laws are different" etc. and I respect all limits on both ends of the exchange but I've been spoiled. In general not only is this practice assumed to be how the session will end in Europe but also in almost every respect the experience is more satisfying. The Mistresses are more beautiful, much more sophisticated and frankly quite a bit more experienced practitioners than than here in general.
In Germany-there is actually an independent organization that "certifies" those it finds that meet their qualifications for best at what they do. They also have a category of Mistresses called "Bizarre Ladies" that are "touchable".
I guess just a much longer tradition of acceptance (and now legalization) in almost every Northern European country leads to so many more woman practicing BDSM. The studios are also much more sanitary and luxurious since it's all legal.
More reason to "legalize it" here if any is needed.