This comic is by Iwano. You can buy it here: http://viid.me/9MwbT

Iwano's twitter account is here: https://ouo.io/gUhcgM

I tried my best at scanning these pages, not really that familiar with scanning comic books and such. Hopefully this will suffice.
This is only in Japanese, and I'm not familiar with translating. Google translation (the phone app) gives broken English as always lol.

Hopefully, you enjoy this fun belly growth comic as much as I did!

This isn't really my type of thing. However, I did have a good laugh at the pg. 13 spread over two pages.

Base +8

I've shown it to a few friends, they found it cute and funny at the same time. I think it's meant to be both lol.

Base +5