This story is A Weekend to Remember, in which a woman turns fantasy into incestuous reality, retold from the perspective of the woman’s 14-year-old nephew. All the actual quoted speech is exactly the same in both versions, but the dialog attributions, the descriptions of the activities, and the internal thoughts of the narrator have been changed to reflect the different viewpoint.
A Sex Magus Story Nominated Best Erotic Fantasy Story 2022 -- When Seth's newly inherited manor is invaded and everyone is taken hostage, Seth does everything he can to save those he cares most about. But, can he succeed when the invaders are far more powerful and willing to do things Seth has never even conceived of much less imagined?