That's ok if the story will go a long way but it should be happy ending because there is no sexual excitement and eroticism in tragedy. We visit this forum only for fulfilling of our hidden sexual desires and fantasy. If you want to write the story on the basis of real life situations and tragic way then the readers will avoid the story because in real life it is unimaginable to happen such kinds of incest sexual affairs between mom and son or brother and sister or father and daughter. So I request you, please write the story only for fulfilling our unimaginable hidden desires and fantasy where there will be existing sexual excitement and eroticism.