[Otochichi] Kuro Gal Game (Chuppon Onna no Vacuum Fella)

A casual sleepover invitation turns dangerous for gyaru classmate Sayo when she meets her friend Yuka's little brother Ken, whose hidden talent for cunnilingus quickly reduces the confident beauty to a trembling, cumming wreck begging for more. The afterglow shatters when Yuka storms in and furiously declares her brother off-limits to anyone but her, exposing a sibling bond far more intimate than their guest ever suspected. Caught between a possessive big sister who knows Ken down to every mole and a gyaru already addicted to her first taste, the night tips into a jealousy-fueled ffm war of huge breasts, footjobs, and nakadashi stakes.