I have a regular Wg who likes me to choke her, nothing to serious but as said in a certain position when Im fucking her hard she likes it and to have her hair pulled at the same time.
It started with the hair pulling probably and built from there, took time though.
I tried slapping her tits once when I first started punting her and she didn't like that one bit. So I thinks it's more a trust/bond thing.
I've had a civvey (affair with a married woman) where she wanted to be treated extremely roughly (spitting, face slapping, beating, fisting etc) but with her hubby she was vanilla as they come..... strange breed they can be