Touhou - Yuka Kazami's Sunflower Field (Doujinshi) - Vol. 1 Ch. 2 - Flowers and Humans and Youkai and… by Bococho

[MangaDex]

 

[BakedBanana]

"You didn't care about anything of this sort when we had our fun the other day in 'Touhou DJ - Yuu X Rei Chu Chu for Self Use'." (Page 14)

This is real by the way.
https://www.mangaupdates.com/series/uq2ukdh/touhou-dj-yuu-x-rei-chu-chu-for-self-use