Responses
What's the difference between blood and not blood related siblings? They're both incest and if one is okay with you then both would have to be okay with you. And vice versa.
Actually if there's no blood relation then you can't exactly call it incest? Bcs the result of incest is e.g. physical/mental disability which is why it is prohibited in the first place :p
If they are siblings I'm going to (╯°Д °)╯╧╧