Those are things I wouldn't try on a provider unless you've spoken with her about it beforehand.
Everyone has a different definition of what rough is. Slapping
ing her ass isn't a fetish nor do I consider it rough unless the guy leaves a red mark and she screams ouch.
What one sees in porn is often just acting. A provider usually won't discuss what she truly likes with a client because lets face it, most men like to talk about their experiences and we do like to keep some of our personal sexual desires for ourselves/our private life. But, the biggest reason is the trust factor between the two during a sexual experience.