Prompto is having a hard time dealing with and moving past his time in Grelea, and everything Ardyn did to him. Finally, he asks Ignis and Gladio if they can indulge him in some abduction and rape role-play in the bedroom as a way for him to process his trauma. Iggy and Gladio are probably reluctant at first, but reaize it's something Prompto really needs, so eventually agree.