Adulthood

Otonage.
大人気。

Prequel

Maybe I'm Your Steppin' Stone
Kawaige.· 可愛気。
manga

The gentle and delicate convenience store clerk Kenji has fallen in love. Not with someone who would match his personality - but for rude construction worker, Kousei, who is in it more for his body than for his feelings. (Source: 801 Media)

Parent Story

Oo-maji
Oomaji.· 大本気。
manga

The always perfect, model student back then, and now an elite dentist, Souhei, couldn't be more opposite from his childhood friend, Jin, a troublemaker since they were kids, and now a construction worker by trade. But fate seems to keep throwing them together... As they dig into the painful past, their feelings for each other gradually surfaced (Source: Fantasy Shrine)

Spin-off

Dangerousness
Abunage.· アブナゲ。
manga

Kuroda, an oblivioys airhead, has a new site foreman: newcomer Akaishi. Kuroda finds him somehow irritating, but he's attracted to Akaishi's beautiful ass, and Akaishi is affectionate towards him... Even though they don't mesh together, they start becoming closer?! (Source: Original publisher, translated) **Included one-shot:** Oomaji. Returns