Doujin circle.
Circle name: ハートがひとつ (Heart ga Hitotsu)
http://www.dlsite.com/ecchi-eng/circle/profile/=/maker_id/RG14965.html
http://www.dlsite.com/maniax/work/=/product_id/RJ099767.html
http://b.dlsite.net/RG14965/
http://www.dmm.co.jp/dc/doujin/-/list/=/article=maker/id=26560/
