It's based on the game "Kouen Itazura Simulator ver. MAKO" and drawn by the same person who made it, misooden. It's full length is 40 pages and it was released on Dec 12, 2016. Unfortunately no one has scanned it.
There is the twitter page of misoden: https://twitter.com/kodomo_h_com
And here are the links to doujin:
http://www.getchu.com/soft.phtml?id=938343&gc=gc
https://www.melonbooks.co.jp/detail/detail.php?product_id=192112
https://www.toranoana.jp/mailorder/article/04/0030/47/90/040030479032.html
There is the twitter page of misoden: https://twitter.com/kodomo_h_com
And here are the links to doujin:
http://www.getchu.com/soft.phtml?id=938343&gc=gc
https://www.melonbooks.co.jp/detail/detail.php?product_id=192112
https://www.toranoana.jp/mailorder/article/04/0030/47/90/040030479032.html
![Thread watched
[Request] [アリマセカイ] ぼくとお姉さんのヒミツ遊び1.5](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8Xw8AAoMBgDTD2qgAAAAASUVORK5CYII=)
