My Sister Burst In While I Was Masturbating

Original title: オナニー中に姉が乱入！

“Caught in the act—the ultimate intrusion by my older sister.”

While the protagonist is in the middle of a private moment, his older sister unexpectedly bursts into the room. The situation quickly shifts from embarrassment to a series of intimate encounters as the sister takes control of the situation. This entry focuses on the 'intrusion' theme common to the Sister studio's lineup, emphasizing a domestic setting and spontaneous interactions