Iro wa Nioedo http://accumulation.web.fc2.com/

Also known as Okari and Sudou Sakana

https://www.pixiv.net/member.php?id=2313513
http://sudosakana.tumblr.com/

The Reason Flowers Bloom Touhou Project Doujin released May 7 '12 Marisa x Reimu Romance Yuri
The Heart and the Heat Between Us Touhou Project Doujin released Sep 15 '14 Introspective Marisa x Reimu Romance Yuri