Incest AU Jon should find an artifact (maybe Lonely but probably Eye) that makes him invisible and he should use this to spy on his dad. Waking up early to creep into his bathroom and wait for him to come in to pee. Spying on him as he undresses. Watching him from the corner of the room while he masturbates or has sex. Gradually escalating until he’s creeping in in the dead of night to touch all those private places he’s finally been able to see. Fingering Elias open and wishing he had a cock so he could know what it’s like to sink into that tight, welcoming heat, settling for riding him instead. And every time he feels guilty afterwards, but it’s never enough to stop him from doing it again the next night…
And of course Elias is aware, but why would he stop him? He wants to encourage Jon, to allow him to deepen his relationship with the Eye… and of course it helps that he’s enjoying it very much.
And Jon knows he should be taking birth control, should at least use condoms, but that would require admitting he plans to do this again, and often. That he wants to fuck his father while he’s sleeping. So he just rides him, tries to pull off before Elias cums but he isn’t always successful, and within a few months of this all starting he’s finding himself mysteriously bloated, sick at all hours of the day, experiencing curious changes in appetite… slinking off to get himself a pregnancy test. And… of course it’s positive. It’s positive and he’s pregnant by his own father after assaulting him in his sleep for months. And he feels so so guilty but he’s starting to get wet too, because of course the thought arouses him.
Guiltily touching himself in the bathroom to the memory of his nightly visits. How it felt to feel Elias emptying himself inside of Jon, the rush of heat, the fear of pregnancy (now realized, his little sibling growing in his womb by the day)… wondering which night it had happened on.