[Hiiragi Popura] Little Sister-ification Shampoo [Compilation]

A high‑school brother learns his younger sibling has been turned into a cute little sister by a mysterious shampoo, igniting a forbidden romance that teeters on the edge of family taboo. The story moves through a series of intimate, first‑person moments where the newly feminized sister, dressed in a festive schoolgirl uniform, lures her brother into a private, Christmas‑themed encounter. Tension rises as desire and kinship clash, leading to a passionate, consensual climax that explores the limits of their relationship.