"You can suck on my chest as much as you like"

Oono Tsumugi and Ukita Kousei are childhood friends. The two share a secret habit since they were little… Tsumugi lets Kousei suck on his chest. At first, it was just to comfort Kousei, but as they reached adolescence, their relationship began to undergo drastic changes. Is it infatuation? Possession? Or... is it just convenience? Arrogant young master x orphaned childhood friend, a class disparity love story.

Spin-off to Desire in the Shadow of Trees (aka Kokage no Yokubou) (https://www.ebookrenta.com/renta/sc/frm/item/96486/)
Reading the previous work is not absolutely necessary to understand this one