Sono Suki Honto

The mechanic Hase has someone he cannot forget and that someone is Nadaguchi—his classmate he went out with on a punishment game who he later had a bad breakup with. Hase never thought that he would ever meet Nadaguchi again after graduating, but Nadaguchi suddenly joins the company where he works. As Hase spends the following days bearing the full force of the awkward air between them, Nadaguchi suddenly confesses to him!

(Source: Fujoshi Undercover)