"I am usually dom but can be sub sometimes , if you cant take it why expect others to ?
I would say that this highlights an interesting difference between those for whom D/s is a bit of kinky role play vs those who consider it to be a lifestyle choice.
Having had a number of 24/7 TPE relationships in the past it's fair to suggest that some people just don't like the other roles, it's not a part of their emotional or psychological makeup. I could never consider being submissive to anyone, I'm far too interested in being the provider, protector, leader in that sort of relationship. Equally, the submissive with whom I've enjoyed relationships in the past would never ever want to be the one making the decisions. For them, the joy of relief from the burdens of control is all encompassing.
Not all D/s relationships involve pain or discipline, which I think is possibly what you're talking about - for me that is an enjoyable and mutually pleasurable experience. I get off on bringing a girl to the brink of where she wants to be almost as much as she enjoys an almost spiritual experience of being either punished or pleasures, often both, by receiving such ministrations.
It's different for everyone but is waaaaay more complex than just whacking one another with bits of wood every now and again."