Orokamono ga Koi wo Shitara.

After he wakes up in an unfamiliar room, Yuusei goes over his memories with an aching head. Being dumped by his girlfriend. Drinking in a bar. And meeting a mysterious beautiful man in said bar. He slowly remembers these things.

"Do you want to try it with an older man?"

After he was asked with those sweet words, Yuusei had agreed without hesitation, and the two spent a night together. They will never meet again. Or so he thought—but then the two meet again in a very unexpected place...

(Source: Home-sha, translated)