Identify Manga from Fakku Oppai Tag Thumbnail

Hello,

I was hoping someone out there could help me identify what Manga that is used for the thumbnail in the Oppai tag. If you click on Tags and browse down to Oppai, it has this beautiful thumbnail. Anyone have any idea what its from?

https://t.fakku.net/images/upload/oppai-tag.png

I would love to know. Thanks in advance.