You know those storys when the mc's semen is magical, or having sex with him is part of a ritual, or he getting sex is part of the scenario? Is there a name for that kind of story? Where the MC dosen't get sex out of ingenuity, or actuvely persuing it, but the need for others to have sex with him just happens?
I guess it depends on why the other characters want to have sex with the male MC. (And what aspect should be highlighted in the story.) So the theme might be "harem," "mind control," "fantasy," or sth else.
Yea, I gess it's a bit too vague to be a fetish But maybe I didn't explain myself because I wasan't thinking of stuff like mind control. There the MC is actively persuing sex by magical means I was thinking of storys like "You are the last man on earth and required to repopulate" or "Harem Isekai Monogatari", where the MC's sperm is magical, so people have sex with him to enhance their powers, or even my [Arbitrary Anthros/Massive concidence](https://chyoa.com/chapter/Arbitrary-anthros-massive-coincidence-forcefull.1121786) where the MC is mostly passive and an impossible sequence of coincidences causes him to be forced to have sex
I don't know an agreed-upon name for it, but to be clear it sounds like you are referring to stories where circumstances contrive to have the protagonist have sex without him/her seeking it out? I should say that although your examples all technically fit under that umbrella, the hook of each of them might be different enough that the umbrella they fit under doesn't have a distinct and searchable name. Things like "inevitable sex" or "unsought sex" technically fit but I think they each carry too many unrelated implications to comfortably fit every example under that umbrella. If anyone has a good fit I'll be interested to see it.
I think non-con as a fetish tag would normally be used by people searching for stories where sex is forced onto a party which does not consent to it, which I don't necessarily believe fits this bill. It seems like in any of the three examples OP listed, the protagonist or other characters may or may not consent to the sex that happens . Example: just because people want sex with the protagonist and give him/her the opportunity for it only because it will magically enhance their power, doesn't necessarily mean either party withholds consent to it. The unifying thread is that their own will is not what creates the inevitable opportunity/circumstance/requirement to have sex, regardless of whether or not they then consent to the sex.
Could be incredibly powerful pheremones of the MC that result in sexual arousal of those he comes into contact with. He might have no method of controlling this and though not seeking sex is used to it's effect (or not if it is a new developement). Those affected (men, women or all) though aroused might still not be forced to have sex, but those open to casual sex would have an extremely hard time resisting.
I like 'sex magnet'. 'Free use' is another term that might be similar enough to attract the audience that'd want to read a story like this. After all, that's what tags are for.