Big Brother's Friend

Aniki no Tomodachi
兄貴の友達

Sequel

Big Brother's Friend Our Home
Aniki no Tomodachi: Bokura no Ouchi· 兄貴の友達 僕らのおうち
manga

After dating through high school, newly employed Kakimoto and college student Yuya have finally started living together…!? (Source: Kadokawa, translated) *Note: Includes an extra chapter.*

Parent Story

Takara-kun to Amagi-kun
高良くんと天城くん
manga

Takara Shun, a high school student who belongs to a popular group in the class, and Taichi Amagi, a pure boy who is not a conspicuous type but is liked by people, realize their love for each other. Even though they start dating in secret, it is difficult to be honest. (Source: Kadokawa, translated)

Side Story

Big brother's friend
Aniki no Tomodachi: Bangai-hen· 兄貴の友達 番外編
manga

Having successfully passed his university entrance exams and finished his graduation ceremony, Yuuya seems to have everything going smoothly. However, he’s feeling unsettled about the fact that he and his boyfriend, Kakimoto, haven’t been "intimate" recently. Then, they decide to take a trip together to celebrate graduation…!? (Source: Kadokawa, translated)