Most definitely a 10. Most people would find at least one thing that I like to be morally objectionable. I’m extremely into BDSM, and submissive to a fault. Like, I think that submission is better than sex. If there’s a bad thing that can happen to someone, I’ve probably fantasized about it happening to me. Anything from public humiliation to erotic torture. I also enjoy basically every kind of taboo erotic roleplay. Ageplay, petplay, CNC, you name it. As long as I get to feel submissive and lose control that’s all that matters. I’m also aroused by the thought of virtually any human bodily fluid in the right context, although I leave scat, blood, and vomit to fantasy.
In practice though, I’m not nearly as extreme as my fantasies. The kinkiest things I do with any regularity is light bondage, impact play, body worship, and verbal roleplay. My absolute favorite thing though, is humiliation. I remember having humiliation fantasies as young as 5 years old. Most of my kinky desires have some basis in an urge to feel humiliated. I’ve developed certain kinks solely because I found it particularly embarrassing to have them. Even typing this out this comment with the idea that people will read it and judge me is exciting.
I guess I don’t see an ethical difference between fictional “step” incest and fictional normal incest. In both cases it involves people that don’t exist. Plus all the ethical issues with incest carry over to step siblings anyway. The idea that one is ok and the other isn’t seems really silly to me.