Noctis and Gladio are secretly sleeping together. Noctis loves being praised and called a good boy, and soon starts calling Gladio 'Daddy' during sex. Then one day Noctis accidently calls Gladio daddy in front of Ignis and Prompto, or Gladio calls Noctis a good boy. Noctis gets incredibly flushed and embarrassed but also kind of turned on by the other two knowing his kink.