SNOS-093 My Girlfriend's Big-Titted Little Sister is the Ultimate Heroine!? The World's Most Supreme Incestuous Temptation of Secretly Falling for Me and Constantly Pressing Close - Seto Kanna

The male protagonist is in a stable relationship with his girlfriend, but he unexpectedly discovers that her busty little sister has developed feelings for him. This sister, with the allure of the ultimate female lead, relentlessly draws close to the male protagonist, unleashing the world's most exquisite adulterous seduction. She secretly confesses her love through intimate touches and provocative acts, attempting to shatter the sibling-like boundaries and lure him into a vortex of forbidden passion. The story revolves around this hidden desire, filled with tension and temptation, ultimately testing the male protagonist's loyalty and self-control.