Hikoi

When Touya had his first wet dream, Naoto decided to teach his younger brother how to pleasure and release himself. Little did he know that the not-so-innocent act would lead to something else. Seeing his big brother having an orgasm made little Touya develop a desire to have his brother to himself, but knowing that it was a taboo, he kept it a secret close to his heart. But Naoto had his own bones to bury. A change in the family opened all the boxes and the secrets were laid bare on the table... Now they both have to find a way to deal with each other and move on.

(Source: Shinmakoku Scanlations)