Koisuru Tsurupeta Joshi wa Shousetsuka no Oniichan wo Otoshitai!

Hinano is a university student who has a crush on her "older brother" Souichiro, a famous novelist and childhood friend of hers. He treats her like a child, since she grew up with him her whole life, but she is happy to spend her days just being with him.

One day, she ends up discovering Souichiro has written an erotic novel under a pseudonym. And what's more, she is shocked to learn that the heroine depicted is a sexy adult woman: the complete opposite of her. When she switches her clothes to more revealing ones in order to become his ideal female image... Souichiro punishes her under the pretext of a "clothing check!?"

A heart-throbbing erotic love story under one roof with a novelist older brother. ♪

(Source: Bunkasha, translated)