There's an interesting discussion on the ASSTR forum (I know, I thought that site had been abandoned decades ago!) concerning writing orgies by Very Well Aged.
He started out relating how it makes sense to include details (like 'using every imaginable piece of furniture'), and presenting the various options and describing who pared up with whom.
I added my two cents, as usual, by specifying it's important to focus on relevant detail. That detail helps flesh out a scene, that too much detail (specifically about minor characters who never reappear) can weaken a story, and that if it doesn't advance the story, it's better to drop the extra detail. (Making the scene appear 'real' helps advance the story by making it a richer reading experience.)
I also raised an issue I've been dealing with lately that isn't often discussed in group scenes. Specifically pronoun confusion. This is especially difficult in orgy scenes where, instead of an ongoing dialogue between two people, with a stray comment by someone else tossed in, here you have multiple "he/he", "his/his", "her/her", etc.
I ran into this recently when I wrote a gay romance story. My editor practically strangled me every time I used "he said" or "he did", because there was no way to know who "he" was.
The same is true if there are multiple parties in an orgy. You often have to name each character each time they do something, and be very conscious of how you do it as you're writing.
I thought this might make an interesting discussion on our various author's experiences in writing orgy scenes, and which pitfalls they've encountered.