Onii-chan Is Done For! - Highschool ONIMAI (Doujinshi)

Onii-chan Is Done For! - Highschool ONIMAI (Doujinshi) summary: Without being able to return to being a man, Mahiro Oyama stayed as a girl since middle school and now has become a beautiful high-schooler who gets completely dominated by his first friend since the transformation, Momiji Hozuki, who has gotten really tall and became popular with the girls in their school.