The story starts with Nakano an 18yr old Japanese woman who's just moved to Tokyo. She's laying bed in her new apartment listening to her neighbors having sex. The next day she introduces herself to her noisy neighbors Sakurako and Nagisa. The next day Sakurako comes over to help unpacking, and start hitting on Nakano. She tells her she's not dating Sakurako, but then Nagisa comes over and long-story-short informs Nakano that they're just Friends With Benefits, and she starts coming hitting on Nakano too.

What sets this apart from most similar stories is that there is absolutely no jealousy or competition between Sakurako and Nagisa. They're both attracted to Nakano and want to date her. They're both fine with the other one being attracted to Nakano too, and they're both fine with having fun with Nakano together.

It's everything happens implausibly fast, but Nakano doesn't fight it. She lets herself get pulled in by the tide of the other two. There's a lot of surprise and confusion on Nakano's part, but none of the expected emotional stress about how she should only like one person at a time. Nakano likes both of them, and doesn't stop herself from showing it.

Eventually Sakurako and Nagisa confess their love for Nakano, as well as two other characters we meet along the way, and that's where I start having problems with this series: one side plot shouldn't exist, another one is confusing, and those two come together in what feels like a forced and overly complicated scene of "Let's have everyone confess to Nakano at the same time!"

In the end this is a sweet and somewhat erotic (mostly kissing and fondling) story of a really sweet hinge relationship forming. Alas, it is hurt by the Harem genre tropes that seem forced onto it towards the end.

There's a nice, and realistic, B-plot involving Nakano's schoolmate / coworker Akiho who falls for Nakano, while Nakano remains pretty clueless because she is pretty focused on the rapidly growing relationship(s) between her and Sakurako and Nagisa.

There's a stupid, and implausible - but thankfully short - side-plot with the landlord's daughter. And a kind-of confusing side-plot with Sakurako's ex who moves in on the other side of Nakano.

The climactic scene is tropey, and the setup is nonsensical, but in the end our three lovers find happiness together.

I'm giving it 4 stars because the main storyline is good, the B-plot with Akiho is good, the kissing and sex scenes are good, but the climax and subplots with the ex and the landlord's daughter are poorly done.

Note: The erotic aspects of this are mostly passionate kisses and one or two sex scenes that gloss over most of the details and only show boobs.

An English fan translation of this can be found on Mangadex and Dynasty Scans.