@ephemeromorph
Yeah, that makes sense, actually, but I think there's also a specific flavour of fantasy that's associated with delivering, receiving or witnessing very extreme bodily abuse in a sexual context that is definitely more psychological than physical.
Ramming something giant and unlubricated up wherever with zero notice makes sense as a rough sex/quasi-non-con scenario, but doesn't map well to reality for most people.
Similarly, there's also smut that makes much of banging on or opening the cervix and neither of those are particularly fun for most people, particularly when done in the way described in said smut.
(My overwhelming feeling on that is informed by my cervical smears = fine but still not recreationally entertaining, whatever the fuck happened when I gave birth, definitely not. Although I suppose there's a certain peace to be found in the "death would be better than this" sensation. 😶)