Taken from his pixiv: http://www.pixiv.net/member_illust.php?mode=medium&illust_id=37743745
From Eroquis's website,
[Ttp :/ / eroquis.com / ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○. Html] ※ After Copy and paste in the URL bar, was added to the "h" in front, please link to put the password in ○.
If someone can figure out the password, we'll have access to the high-res version of this doujinshi.