Here's some of the mechanics of an unbirthing age-fuckery/reincarnation porn AU I have for my OCs :} Implied incest, age gaps/mdlg/mdlb, and explicit digestion below the cut
So basically there is a separate humanoid species that is closely related to and genetically compatible with homosapiens as well as having coevolved with them, but due to their manner of reproduction they haven't fully integrated into the human gene pool. They're a single-sex species that are both visually similar to cis perisex human women and are more or less treated as such. They reproduce via what is essentially unbirthing/vaginal vore, and their bodies accommodate for that: They're taller and stockier than (average height around 200cm) and have greater strength and muscle mass than the average human, although they're typically a little fat on the surface. Their abdomens are soft and fat to accommodate for their large wombs, which can stretch to accommodate up to two thirds of their body weight during the unbirthing process. Their hips, which are already naturally very wide, are actually made up of smaller fragmented bones connected by a strong cartilage that stretch while they're in heat. (Yes, this makes them more prone to severe hip injury and pain btw, and they must take it very easy while they're in heat especially)
As for their actual reproductive process, after some ample foreplay over the course of days, they'll finally be wet and horny enough to allow their partner (or victim) to crawl inside. This is ideally done with at least 2-3 other people, one to help the to-be mother keep her legs open, one to push the parent/future-child in, and one to give the mother emotional support. This is a process that is equally painful and pleasurable for the mother. As for the other parent/child? They are being completely squeezed, almost crushed by their mother's pussy, but an aphrodisiac in her juices makes the process absolutely euphoric. Once they're fully inside her womb, they'll be slowly digested into pure genetic material over the course of on average 12-14 months, depending on how big they are. The first 3-5 months are spent being digested. The digestion process is painless, and during the earlier parts of the process when they still have somewhat of their old physical form and consciousness, they can interact with (and tease) their mother. Once they're done being digested, they reform into a fetus the way we're more familiar with, but with a mix of both their original and their mother's genetic material, as well as their memories, which begin to return around ages 4-5. There's a chance their sex may change, or that they might be reborn entirely as their mother's species. Whether or not they remain mother and child, if they resume their original relationship, or if they do something else entirely is up to them.
