Pastel is an endless series of chapter after chapter involving the protagonist, Mugi, having erotic fantasies about nearly all the women in the series. It's also an endless series of the protagonist being cock-teased, cock-blocked, tortured (physically, and sometimes violently so, as well as emotionally), humiliated, treated like a punching bag, like a "volunteer" guinea pig for pain-inducing experiments, like a servant, a housecleaner and, especially, like an unpaid and unappreciated cooking robot.
As with many harem series like this, it is unfathomable what the women all see in such a pathetic milquetoast wimp of an MC that would make them want to seduce him, but about a dozen of them try: almost all the women the series try at least once except Yuu, who becomes his girlfriend early on in the series. With her, apparently the only thing allowed before marriage (at least with Mugi) is a non-passionate kiss once every 30 or 40 chapters. But, with 219 chapters, that means he gets to kiss her about a half-dozen times or so...