Why did I even watch this? One thing I can say for sure this anime taught me a lot about one word „ichaicha“. It means “make out” i.e. kissing, touching, etc. It’s been while since I watched some crappy harem anime series. As it is usual for any harem that does not fall into hentai category, there is no real action happening. What you get instead is bunch of girls, mostly crazy i.e. resulting in a lot of comical moments, to compete over generic onii-chan.
The premise of story is quite simple. I’m just talking about it so you would get the picture, what the story is like. We have the onii-chan, who wants to become light novel author. However he is beaten by his all-perfect little sister aka imouto in contest for publishing. He has no idea that her work is not just mere fiction but embodiment of her lust for onii-chan, thus “the story of little sister, who is troubled by her passionate love of her big brother” is born. She ask him to pretend he is the author. This leads to situation, where the onii-chan is pursued by other women, like his classmate, who is also writer of light novels, or “ahegao double peace” artist, etc. This forces tsundere little sister to become more proactive and bold in her advances. Onii-chan on the other hand will have to awake his love for the little sister ... the end.
Animation is simple and generic as far as it can be. Opening theme is good, but rest is ok.
So, it’s so bad that it can be funny at some moments, maybe. Would I recommend it, hell no. Unless you have a lot of time and no shame stay clear of this. Watch something good or even average instead.