One thing weird with threesomes in coc2, that's probably the most divisive thing, is that the player has no option for boundaries, even while characters themselves can. Like how someone brought up the arona/ryn threesome is just PC doing oral, ryn getting the booty. Generally to me in threesomes with 2 dongs, it's like the preferred order is v>a>m. Someone else with the v feels closest to factual cucking or pregnancy risk, removes a level of intimacy or whatever. There's the stud element where seeing someone else bang them makes you want to bang them and push out their splooge but still more offputting. Course even oral with someone else would feel like you were/literally are consistently in contact with someone else's splooge when later kissing etc which is a issue. But even in more dramatic adult stuff, butt and mouth are usually considered more detached. It's like the more monke brain version of emotional/sexual dynamics. Person giving a rj feels less intimate than kissing/missionary etc.
There's different layers. Like if a male was ok with sharing but v was restricted (like in game aurera), or a female that also had v restricted to a certain character. Could also make weird variations like cait but kinda pushing it, and most commonly accepted order still seems to be v>a>m throughout erotic stuff.
Dynamic wise, like if you had an in game threesome with brint, and PC and him fist bumped and tag teamed someone, there'd be a good sized appeal for that. For detached NPC content or brothels etc with him, even bigger, no emotional stuff, but he's nearly always wrote as being bigger, better, etc sexually. Elthara pregnancy being bigger etc. It's written explicitly with a cuck/ntr fetish edge not hole bros or equals having a fun time. Dom arona, same thing. Females face everyone getting off on Cait, wanting her body for trade etc, themselves just being the opening act.
Particularly sketchy when PC can fine tune their genitals to be friggin biologically min maxed, kas is supposed to be walking sex and the PC is currently able to be well on the road of matching her perks, size and output. Tanuki balls give one finger to anything else someone may have, evergreens fertility treatment gives another, fine tuning size, attachments and knotting gives the hand. Female parts can receive the same tuning. Presence/charisma/charm can be maxed out and you can have prior training as a royal ho, but with all that, writing wise, brints still top stud, and caits top sex icon, others are great, player is fine. It limits audience a great deal when the player plays backup instead of being at least as good as them masculine or feminine wise.