If you're invited to have sex as the bottom and others decide to join, how about allowing them to take lead? It can honestly get somewhat stale with only one person as the lead. Or you could let them decide whether they want to participate as a top or bottom depending on their current mood and general disposition. I kinda like that idea, though I'm not sure how hard it would be to implement
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The issue with that is that the sex as dominant conversation option is meant for whenever a character/player wants to be the top. There's the possibility of scenes with shared lead where some characters have their lead disabled (effectively making it a scene with some characters acting as top and others acting as bottom), but I don't remember what the exact requirements to get them to trigger were.
I think there was that scene with Val and Mir after breakfast where you and Val would share the lead with Mir being locked in as a bottom if you decided to side with Val. Don't really remember any non-story scenes where it happened though.
I mean I get why it works the way it does, it was just something that I noticed - in part because the story scenes introduced something like that. And after several instances of being immobilised while the top was busy with someone else, I couldn't help but wonder how to get a bit more variety