Incest patch? The game doesn't feel like there's actually incest when you rename the characters to Mom and Sister cause others would call them Mom and Sister too and the way they talk and interact also makes it seem like they aren't related eventhough you said that they originally were while other games which avoid incest make it obvious that they are totally blood related and there's an incest patch to change the relationships so maybe you could create an incest patch for those who want it.