Koibito Keiyakuchuu ni Tsuki

Company employees Yanaka and Moriyama are lovers...... Well, pretend lovers. After being repeatedly approached by women he had no interest in, Yanaka was at his wits end and asked his friend and colleague, Moriyama, to pretend to be his lover. In exchange, he'd do whatever Moriyama asked for. Well, what Moriyama asked for was... Yanaka's body! Moriyama, showing this side of himself, flusters Yanaka, but Yanaka does eventually surrender himself... How will a relationship started from a lie pan out?

(Source: MangaPlaza)

Note: Includes two extra chapters.