So my PC sexed an NPC once.
General sequence of events: the NPC was set out in a public place. There were a number of different PCs who rolled in to play with her, as you might expect! People were excited. The RP was generally pretty fun and funny as I recall. I think there were about 6-8 other PCs in and out of the scene, not including my PC or the NPC.
It was generally known (ICly and OOCly) that this NPC had access to some top-tier weapons. The NPC was there as a diplomatic envoy to reestablish ties, and a previous treaty with her people had indicated they would supply these weapons, so there was a lot of expectation that that would be a part of any reestablished treaty. My PC was a real flirty, extroverted, show pony type who totally wanted one of those weapons, so when he realized the NPC was there at his favorite bar, he set about trying to impress or charm her into promising him one of the weapons. He was generally dumb and reckless about it. In his attempts to impress her, he shared with her some secret info. It was dumb of him to share, because it was the kind of info that other people in the world might use as reason to get him killed, but it was early in his introduction to things. Why not use a dangerous secret to try and get a cool thing from someone who could kill him in an instant!! Sounds fun!! In the nature of group scenes, this was one among several other angles of conversation going on. For further context without actually revealing the entire secret, it was not 100% unique on the grid, but it would have only really been present for a few PCs.
The NPC had specific reason to be interested in what my PC shared with her. He didn't know it at the time ICly, and I didn't even really have an idea of it OOCly. Long story short, she became much more receptive to his general flirtatiousness at that point and took him to bed after several hours (as I recall) of the public scene. There was, indeed, some posing of sexual stuff before it hit a FTB point, mostly because of the late hour at that point. If it had been earlier, maybe it would have been played out? There was notable character stuff that certainly made it interesting.
In the end? He didn't actually get the weapon from her. She did intend to, but the diplomatic negotiations fell through with the actual people in charge, and she and her fellow NPC left town. However, she reconnected privately a while later with a different PC who she had also encountered in a public/open scene and who had impressed her into being quite fond of him. (In fact, I believe the PC specifically was telling off other PCs in the scene for being really rude to the diplomatic envoy NPC. Being interesting and not super rude to the NPC went a long way.) This other PC was given a number of the weapons to distribute to other PCs he felt were worthy of them and would use them in defense of the city and whatnot. He chose a variety of PCs from different factions of the game, the majority of which were commoners or lower-level nobles who he thought would have less access. My PC did end up with one of the weapons through this route. I am absolutely aware that there are players who were angry about this because they felt it was fucking his way into a cool weapon. (And, to be fair, he didn't make a secret of the fact that he'd slept with the NPC, because at that point he was particularly dumb about saying everything that popped into his head like an excitable puppy.)
So! Fast-forward...a while. There is now a kid from all of this. The kid was, in fact, the point of it for the NPC. I can't fully unpack it without revealing certain secrets that are still in play, but suffice to say there was specific reason rather than a more general desire to just get knocked up by somebody. The kid actually blew up quite a lot of my PC's IC plans, considering he was in a position where he wasn't allowed to have kids, and there was a lot of fallout before it was all settled. In the end, he had to be released from certain vows, and he gets to have the kid around half the year. (The other half, the kid goes back where his mom lives.) The kid is weird and creepy and delightful because he is growing up half his life in a very weird and creepy place with his mom's very weird and creepy people. His presence is generally limited to color in my RP for part of the IC year. There are multiple PCs who have really leaned into interacting with him when I've brought him out, so I think that's a benefit, and I try to just background him for people who aren't interested.
My PC and the NPC in question never hooked up after the one time; the limited contact they've had in the couple years has mostly just been about the kid, and at this point the NPC is largely out of play. I'd say that during that initial time, the NPCs were put into public spaces that were generally accessible for a lot of PCs to try and peek in and engage. I guess you could say that those PCs who sought out those scenes to engage had equal opportunity to flirt like idiots like mine did, and other PCs might have very well had different ways to make themselves of interest. It's true, however, that the NPC's source of interest in my PC in particular was relatively unique.
All that said, no one's really interested in hearing my inside take that I thought it generally felt reasonable, because my opinion is obviously biased and will generally have to be seen as someone who is looked to have benefitted from all of it. Most of this took place largely a couple years ago, but the effects are still continuing throughout the game.
So mostly I thought I'd share an actual story as a potential example for people to pick apart! For me it did not feel gratuitous or inappropriate, and I think I would have felt the same even if more of the sex part had been played out, but obviously this is like the very definition of YMMV. I just thought it might be interesting to toss out an actual scenario that happened. My general opinion is that healthy NPC play lies somewhere between "NPCs have no business messing around with anything sexual with PCs" and "NPCs can spend their whole day TSing the same person forever and giving them all the free loot." I do also think it's the case that players will always make assumptions about what exactly is going on behind closed doors and that our assumptions are probably more often inaccurate than the reverse.
