After the events of the movie, Jyn, Cassian, and Bodhi get sent to Tatooine for some reason (you can handwave this for porn purposes but I was thinking maybe a mission for the Rebellion, perhaps to find Luke...or just because they got lost or whatever). They pick up Luke in a cantina and have their way with him. You can get as kinky as you want, as long as it's all consensual. :D