I think the concept is kinda weird but I think its sorta hot because of how natural it feels in terms of normal professional porn, if that makes sense.
I consider myself a "porn hipster" when it comes to this topic. I had been watching this kind of porn as a teenager, before it was mainstream and on major websites like pornhub. I don't watch it much anymore, I suppose it might be a subconscious hormone kinda thing that teenage boys like. And we all know that teenage boys make up a very large percentage of porn video views lol. Must be the feeling of it being something your not supposed to watch which makes it kinda taboo.
I feel like it's more that it's the close relationship that is interesting rather than just the incest part. Like you could replace sibling with best friend and it'd have the same effect for me. It only gets weird when people actually want to fuck their real family lol
Doesn't do much for me but I get why others would like it. However, it gets REAL annoying when it's taken over everything, so basically anything involving a college-age girl HAS to be stepsister incest. Or stepdaughter. Give me my variety, man. Whatever happened to "hot neighbour next door"?