Gogatsu no Hana wa Mada Sakanai

Tsubaki is a well-liked and very rich high schooler whose mother usually works. One day while coming home from school, Tsubaki was shocked to find that his mother brought back her new boyfriend, Reiichi. Reiichi is a nice person, but he likes touching Tsubaki intimately which confuses the young and innocent Tsubaki. After Reiichi confesses to falling in love with Tsubaki, he is even more confused.

(Source: Mangago)