[Natsukawa Fuyu] My Little Brother Can't be this Cute! (Nyotaika Dynamites!) [desudesu]

When Kousuke notices his sister Rikino has undergone a startling physical transformation, a domestic dispute over stolen ice cream turns into a much more intimate encounter. As Rikino's body continues to change in unexpected ways, Kousuke explores her new, softer form, leading to a series of intense, sensory-filled moments. What starts as a sibling rivalry quickly evolves into a surprising discovery of new sensations, as Rikino finds herself overwhelmed by the pleasure of her evolving body.