Honestly, seeing as how this discussion went, I kinda want to ask what would be considered "acceptable" for Sex Scenes in the game? I don't mean what kind of partners or sexual acts, but more how would people pref it presented, other than the "Not at All" side of things cause that does answer itself. Like would people prefer a fade to black, fully animated erotica with anatomically correct organs, foreplay only, fade to black with written description of the actions narrated by the narrator, etc etc?
Definitely not that last one. Visual sex scenes
can be useful for purposes other than porn; you see the characters' expressions, them bonding, etc. But a narrated or text-only description of sexual encounters just seems gratuitous and like the goal is erotica.
...then maybe some narration of the important emotional bits, don't really want or need the actual intercourse to be described, just what it means for the characters and their relationship.
This would be better than narration of the actual intercourse, but I feel like this is what the after-sex scenes are for. The couple is laying together after sex and through their body language and dialogue (maybe internal thoughts for the PC, probably more applicable to Origin characters) you can learn what it means for the characters.
Alternatively, ^ can be presented in dialogue the morning/days after sex.