[Yamamoto Yoshifumi] Kinshin Choukyou Ane Dorei

A sister, restrained and trembling, is forced into a degrading training by her brother, whose cruel grin signals his complete control over her body. He taunts her with promises of further invasive acts, escalating the power imbalance and her helpless surrender. The relentless intensity of their twisted dynamic drives the story toward an inevitable climax.