Hi adelina. That's a good question - especially from someone like you who I know tries hard to understand the whole submission thing in general.
M/s is really just a more extreme version of D/s, I think. Both have the same underlying elements. However, I think objectification of the sub/slave is more prevalent in M/s as both partners get their jollies from that. Also, I think "slaves" tend to be more subject to their Master's pleasure, and are subjected to more extreme sides of discipline and bondage --- well, just BDSM in general.
As for RG's comment about the "decision being [his]." For starters, in actual discipline I have no choice but to comply regardless of whether I want to or not, and I have chosen this. The premise is that that it's good for me. At the exact moment I may not think so, but the whole DD thing does indeed (another thread! lol) keep me grounded and feeling "cared for" and accountable. Of course, along with that comes the trust and communication as to what requires "discipline" and "control", for if I was being disciplined unjustly continuously, things wouldn't last long!
The assertion of dominance in play, however, is something that is very erotic. The whole illusion of non consensual, of having no choice or being unable to get away plays a part -- when, in reality, of course "play" can be stopped if I truly do not want to do it.
And, despite this dominant role RG has in our relationship, he also loves me and cares about me and is considerate of how I feel. Just like he would never force sex on me if I truly didn't want it and use me for his purpose only despite what I wanted, he would never force me down to spank me just for his pleasure if he knew that I really, *really* did not want to play.
The protest I was making is normally part of our playful banter, so he had no real reason to suspect that I was NOT in the mood. I chose to submit after the weak protests did no good of my own volition, as an exercise of submission. What *he* said in regards to being able to do it when he wants, is also part of our banter. Kind of "this bottom belongs to me". I could have pushed myself up and said assertively, "I *really* don't want to do this. Forget sex. I'm just going to bed."
Believe me. he woulda got the message then -- AND he woulda respected the message. You've met RG. You know he's really just a big teddy bear!
sarah