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.