I stumbled upon a conversation recently where people were debating the difference between Sadism and Abuse. They were using a scene from one of my books as a discussion point, which is perfectly fine, I'm flattered that enough people had read my book it could be discussed this way. I didn't enter the conversation because I didn't want to agree or disagree with anyone. I know my intention for that scene - but however they read it is the way they read it, and that's the correct answer for them. A squick for me is a turn on for someone else, and a squick for them might be a turn on for me.
My definition of consent allows for there to be no safeword under certain very defined circumstances. I don't think that can happen overnight. In real life, my husband and I were together for years before we began playing around with periods of time without a safeword. When we first started playing around with it I was very specific as to what he could do that I could not safeword out of. We put it in writing to make sure there were no misunderstandings about it.
We've been together for 15 years now (married for 13 of them) and we rarely use a safeword. There are certain bits of edge play where we use a safeword, and if we try something new then I have a safeword. Otherwise, if there is a problem I tell him the problem - my arm is falling asleep, my leg has a muscle cramp. He usually knows something is wrong before I say something, though.
In any relationship there should be give and take, so both parties get what they want. In a vanilla relationship that probably means both parties go down on each other. Or perhaps one gives massages and the other gives blow jobs. Whatever makes them happy.
In a kinky relationship sometimes that means one person might enjoy medical role play more than the other, while the other partner enjoys sensory deprivation more than the other. So perhaps the Top will provide sensory deprivation for the bottom even though he's not that interested in it from his end... and the bottom will submit to medical play more than she'd prefer because she knows it's a huge turn on for her partner. If the rest of their kinks match up then making concessions for these two kinks isn't that big of a deal in the bigger picture.
In Safeword: Rainbow we see one scene where Tyler spends a lot of time working a flogger on Viv's back, getting her to sub space in an extremely pleasurable way. He's focused on her pleasure in that scene, thinking of what he can do to make it good for her. Later we see him putting her through a very rough scene -- one designed to feed his own sadistic needs. He tells her at the beginning of the scene that, "Some nights being my property means you get pleasure beyond your wildest imagination. Tonight it means pain." During this scene he employs a trick that deliberately keeps her out of subspace because he wants to see her hurt. He doesn't want her to float off into subspace where she can turn the pain into pleasure.
I've heard from so many people about this scene. Some loved it, telling me it was perfect and that it hit all of the right buttons for them. Some people were incredibly uncomfortable with it, but still appreciated it for showing them how something they have no interest at all in doing can be a huge turn on for other people. It's something they hadn't considered, and they appreciated the idea behind it, even if it made them squirm. Others see it as abuse and draw a line in the sand with that scene, saying it went too far. And that's okay. There is no right or wrong answer to how someone reacts to that scene. All reactions are an honest reaction.
Does consent always mean it's not abuse? No. I can think of instances where I feel something is abusive even when there is consent. For instance, I am uncomfortable with situations where someone with no education and no marketable skills and no way to support themselves feels they have no choice but to consent, for fear the person will break up with them and ask them to move out.
What about you? Where do you draw the line? If there is no safeword and the submissive has agreed to that, do you still consider it abuse? If the Dom is only concerned with his own pleasure in a scene every once in a while, does that make it abusive to you?
I think perhaps we're reaching the edges of SSC versus RACK. But this post is long enough so that will have to wait for another day.