The most important part for me is how well written the relationship is, so between different games I could like different constellations. But in general it would probably be brother/sister. I think it's the most "realistic" for lack of a better word
i will take anything main family related tho a game with a full family get toghter mum son daughter and dad is the best but sooo rare, just found golden mean which seems to be going that way but has long turn around times.
What is your favorite incest relationship?
The good old mother-son or brother-sister?
Maybe father-daughter? Going a bit on a safe route with aunt or cousin?
Father/Daughter and Mother/Son for me. Brother/sister does basically nothing for me... And step-incest doesn't either, which is a bit unfortunate because for the past few years it seems like most porn studios are only doing explicitly step-family stuff. To the point of being so cautious that they unironically use terms like "step-aunt" to make extra sure you know it isn't actually taboo.