Responses
Word on the net says it's an illustration by an artist called Enomoto? Not a manga, I'm afraid. It's a novel called "Confessions of a Pervert" (or so Google translate says)
http://www.amazon.co.jp/%E5%80%92%E9%8C%AF%E8%80%85A%E3%81%AE%E5%91%8A%E7%99%BD-%E3%82%AC%E3%83%83%E3%82%B7%E3%83%A5%E6%96%87%E5%BA%AB-%E7%B6%BA%E6%9C%88-%E9%99%A3/dp/487724591X
http://www.mangago.zone/read-manga/ubatte_choudai/mi/mi_chapter-1/2/