I like the idea of it as a way to get to know his soldiers better. (I'm sure that's already been the plot to a military themed porno)
He sits on his throne, they come up one by one (at first) start linking names with smells and heartbeats. Take note of who's eager to please, who's apathetic or resentful but tries hard anyway, who tries to dominate him, get an assassination or two out of the way ("You, taste his cock for poison")

Less interesting ones get just enough to make an impression. More interesting ones take longer. He might hold some down, some he might order others to please him and see how they go about it. Some might get his cock in their mouth or his fingers in their ass. The billy clubs have to be involved at some point.

Maybe there's some fucking for rank among the ones he's already had. Maybe they start the orgy in the throne room to get prepped for when he calls them up to his throne. Maybe he takes breaks between magic meditation erections to walk the edges of the fray and use his fingers here, a billy club there. Maybe the really special ones get ridden cowboy style because why the fuck not, it's porn logic