Group
Group is sex with more than two people in it. As a theme it covers a third person joining a couple, a foursome, a reverse harem with one woman at the centre of several men, and the ensemble scene where the group itself is the point. Readers who tick it want two things fiction usually fails to give them: everyone present as a person, and a clear picture of what is happening.
Cast size is the hardest test there is for a story engine. Two people are easy to keep straight; five are not, and the failure is instant and visible: the quiet one suddenly talks like the loud one, a hand belongs to nobody in particular, someone who left the room is back without arriving. Readers of reverse harem in particular know their men, and a story that blurs them is a broken story.
How the engine handles it. With Group ticked, the story state does most of the work: every person in the scene is an entity with their own facts, and the engine keeps spatial and physical continuity across all of them, who is where, who is touching whom, what has already happened. The craft rules that apply to every scene, positioning, contact points, the loop of action and response, are applied per person. The plan gives each member of a group their own thread, which is what lets the shy one have his section and the leader pay for something he said earlier. The reverse harem landing page is about the version of this theme that is a whole genre. Every person in the group is an adult; the limit does not bend for numbers.
Your stories are encrypted at rest. We can read them to write them. Nobody else can read them.