Kina Yumaki, a younger sister, is penetrated by her older brother, and even when their parents return home, her brother won't stop thrusting. (DVAJ-376)

My younger sister, Makina, takes advantage of her brother's eternal virginity by showing him her panties and demanding his allowance. The brother becomes increasingly frustrated by Makina's ostentatious displays of sexual prowess, always ending up last, and loses his mind when he sees Makina's vulva and inserts his penis into it. The raw sensation of her genitals is so intense that the brother goes berserk and ejaculates inside Makina's vagina. And it doesn't end there… I find my sister running away in the hallway and the bathroom, repeatedly ejaculating inside her! Even when her parents return home, she thrusts her penis into them, seemingly on the verge of being discovered! Despite being her own brother, Makina's sanity is on the verge of collapse, spending all day thrusting into him!