Well, xstoryplayer comes pretty close, and from what I have been reading regarding updates and progress on the next version, it could be one step closer.

For me the perfect sex game would be a modable open world where you can create and edit characters. New positions could be unlocked as you progress or achieve certain milestones. Npcs could have different preferences, which will lead to more positions being used in more ways, rather than having a huge list if positions that are hardly used. Relationship building with the npcs would also be required, no jumping right in and fucking anything that moves. Also, one price for the full game, no micro or monthly payment crap

hello xstory: the perfect game. we have to consider everyone. everyone is different,and desires,so you have to take that in consideration.make a game for everyone that can enjoy playing.let the player decide how it will be played a list of different character just pictures. no names, no age for character,any thing goes the player decides how it will be played.you have to be opened minded and willing to spend a lot of time and money.there should be no restrictions on the game.cost 75.00 a year no up grades one installment. the player decides his or hers destination. sincerely phillip lumley

My idea of a perfect sex game:
Xstory ya is great, other software games also...
but nothing compare with and i asure you, perfect sex game is in real life with real person

Unless the real person scream annoyed if you spank her )

Some things can only be kept as fantasies and a bdsm game is better than a bdsm movie.

That would be a really great game. I hope they'll hear you out and implement your ideas to xstory lol. I've been playing several xxx games and none them has disappoint me so far. But what's disappointing is the tech problem somethimes. I have google daydream and get most of my games and movies in this site http://www.vrpornmovies.net/en/google-daydream/ and other resources. Maybe before perfecting the games, we should first wish to make the technology a bit perfect.

Xstoryplayer is technically and visually superior to any simulator I've seen before. I think all it's lacking is the character interaction and broader established setting you can get in multiuser environments like Sociolotron and Second Life. But I'm interested in how NLP will progress, as that can add the character to bring it to life. There has to be credible context to the sexual activity in order to make it immersive. If you can't suspend disbelief in it, it's pure detached voyeurism, and that fails to keep the user involved.