[Horihone Saizou] The God In The Bottle {Ero-Otoko} [Decensored]

When his little sister's friends corner him to prove they're all definitely girls, a hapless older brother discovers every one of them hides something extra under her sweater—and his sister Kano's package is the biggest of them all. A pint-sized imp-god with a taste for semen takes a liking to him, magically swelling his manhood past even Kano's formidable size, a blessing that backfires the moment the girls gang up to test his upgraded equipment from every angle. By the end, Kano has claimed her onii-chan as her personal plaything, and he's resigned to nights of being screwed to sleep by his own insatiable little sister.