I remember a long time ago reading a manga, pretty sure it was lewd in nature, that had a lot of transformation themes in it. There were people living underground/in the sewers or it was post-apocalyptic. I remember one person that became some sort of caterpillar thing to have someone else's babies. Pretty sure things happened multiple times. Does this ring a bell to anyone? It has been many years since I have read it, but it just popped into my head and I was wondering if I could find it.
