Thank you for your response Daumon, but I wasn't wondering (so much) about topping during a set scene as I was about rest of the time, in a (everyday/constant) D/s relationship (that isn't 24/7 total power exchange).

I think fetishdj came closest to my conundrum - where do you draw the line about whether a sub is being manipulative or a teasing and/or bratty sub more or less playfully testing/challenging her Dom? Or do you simply don't stand for either i.e. you make no distinction between the two?