Proust no Koibito

Working in human resources at a major pachinko manufacturer, Misaki comes off as a serious and inflexible person while on the job. However, in his off time, he lets loose and enjoys himself by spending time at pachinko parlors. While out and about, he meets an inexperienced-looking young man named Iori and is interested in the rare brand of cigarettes he possesses. Influenced by Iori's sense of distance and the smell of cigarettes, Misaki invites him to spend the night at a hotel and "do things that real adults do." But what happens when the next day, a new employee is late to the company's welcoming ceremony!?

(Source: Gentosha Comics, translated)