Howdy.
I'm into a variety of really niche shit but it's all hard to find without running into unrelated stuff. Basically, it all centers around rapid pregnancy and birthing (or egg-laying) as either a sex act or a fact of an average day for anyone with a womb. Extremely casual sex/nudity are huge plusses for this, as is freeuse, but I'm actually not into pain-causing elements, and orgasmic birth is my biggest kink. (Also very hard to find on its own for some reason.)
Some examples I have on hand include:
https://archiveofourown.org/works/26265058/chapters/63936583
https://archiveofourown.org/works/27823828
These hit a ton of stuff I like but the focus on loli shit with the sister is way too much for me and the second one takes a lot of weird detours. But this is it, the casual and pleasurable approach to pregnancy and birthing. I do highly prefer fpreg to mpreg and get more out of the fpreg stuff in this, but the way this does mpreg definitely isn't bad.
https://imagineyourepregnant.tumblr.com/post/722845792325582848/imagine-you-went-on-a-date-but-you-were-both
This does pretty well for the same reasons, but it's short and there isn't much else like it on the blog.
https://imagineyourepregnant.tumblr.com/post/629349693797826560/the-bakery-chapter-3
This series gets the casual and rapid aspects well but still has painful births and the characters are very xhamster-stock-video in a way that gets annoying.
TLDR I love "breeding paradise" type scenarios, where rapid pregnancy and orgasmic birthing are seen in-universe as casual, fun, and common. This is really fucking hard to find for some reason, despite feeling like in niche spaces it should be more common. Is someone out there keeping a hoard of content somewhere? Or just post orgasmic birthing fic/art, whatever.