Manga written by Mangaka Yama Danchi:
Blue Archive - Chiccha Sensei ga Asuna ni Osowareru
Blue Archive Onee x Shota H doujin by Yama Danchi. Initially was uploaded in 3 parts. The author has several more short doujins featuring the same sensei. Note: it also has "urination" and "internal urination" tags.
Chapter 14
6 months ago