Switching or changing roles to be honest is something i dont understand in the sense that being dominant or submissive is a personality trait, ie. you are either one or the other, thats not saying that a submissive cant be assertive or a dominant cant be passive but in the context of bdsm as far as im concerned how can one go from being dominant say in one session to submissive in the next. That being said there are situations where people have started off as either D or s but then discovered they are happier or more suited to the opposite role, that i can understand but to regularly switch i cant.
So no we dont switch, that would definitley be a deal breaker for me but its something i dont think/worry about because i know 100% that it will never happen, thankfully. Occasionally He has mentioned that He may want me to hurt another (simply because i think it amuses Him) and its something i always have and always will protest against, i have no desire to dominate or hurt someone im quite happy and content being on the receiving end (yes even when its something i dont like). So then there is the dilemma of what if im told to, i cant refuse well i could but that would just incur punishment for not obeying, on one occassion i was told to pinch another womens nipples, i didnt like it, didnt want to do it regardless of whether she liked it or not..i was not happy at all.
As for physically fighting back, with Him no it has never crossed my mind to do so and i doubt it will, i have on occassions verbally attempted to avoid something and its pointless gets me nowhere just makes things worse. There has been only one occassion that i can think of where i have attempted to refuse to comply, the last time we was together i clamped my legs together when i was told to open them and i resisted, He slapped my face (which i like, but if i had still refused i have no doubt it would be something i didnt) so really its pointless, im never going to win if He makes His mind up im doing something...im doing it.