Most of the mpreg I've read, there's a Caesarian involved. Once there were eggs involved, but the babies did turn out to be ducklings, to everyone's dismay. (Stargate Atlantis lends itself to weird technology doing weird thing.)

What little mpreg I've run into (like, four fics) two were angelic births that were spiritual/metaphysical and didn't involve actual physical birth, even if the end product was physical non-vessel-having. The other two the writers skipped right over the physical act of birth. Sex, then babies.

Well, I figure Supernatural fandom will either go egg, or go grace. How are you gonna know?

If Cas is Mr. Mom, then yeah, egg or grace, because angels have wings, and therefore are the ancestors of birds (and dinosuars, I guess). But the other half of Supernatural fandom is wincest, and so those two options are mostly out.

I think that there needs to be an additional orifice. An egg coming out covered in feces is one thing, the important part is protected from contamination. But a mammalian infant coming out the craphole, during a delivery that could take hours, is just wrong.

Oh, the hurdles writers will jump through or simply dodge so that they can keep the buttsex and have babbies too is incredible.

In the Avengers fandom there's some mythological canon for MPREG. The writers either gloss right over Loki's birthing the offspring, bring up shape shifting, or go the "Alien, alien, totally an alien," route. In one story he was like an ant queen, popping out eggs all over the place.

I don't recall any commentary on the baby-worthiness of Loki's ass. If he's birthing foals, one would hope it's more capacious than average.

So MPREG babies don't usually come out of the ass? I'd just heard the term butt babies and run with it. That's so judgmental of me. I should be ashamed.

However, I think you were just telling me about Wincest MPREG, and I really--just tell me about full on bestiality MPREG, because at this point WHAT THE EVERLOVING I DONT READ THAT.

I figured he gave birth as a horse then changed back.

Star Trek has some awesome MPREG. They're always running into aliens who not only make them do it, but give them the womb to carry it and sometimes a magically appearing vajajays at just the right time. It's even funnier when it happens in the Mirrorverse. And Invasive Alien Parasite Makes Three. I laughed until I cried at Kirk's stages of grief. If you do decide to read this, be warned, there is dubcon, noncon, attempted forced abortion and yet it is still one of the most hilarious things I've read in a long time.

The Supernatural MPREG I somehow made it through has so far not involved attempted abortion. I wonder if there's any Godstiel or LeviaCas with that? It would be theoretically interesting, but oh god, don't make me eat that cake.

I think a lot of the Omegaverse stories have, like, a dual-chambered ass or something. I mean, it's self-lubing, so I assume it's also self-cleaning.