Trigger Happy Session

Chihiro is a high school student whose dream was becoming a basketball player, but it was cut short due to an injury. One night he gets caught by Ryuji, creator of the wall art which Chihiro and his friends were messing up in the park. At first, Chihiro was scared, but attracted to Ryuji's good looks and then somehow became his assistant. (Source: Kaiohsha, translated)