Sarina Kurokawa returns to OPPAI with her bust upgraded from F-cup to H-cup! Things were going smoothly with her boyfriend—until he unexpectedly meets her older sister, sparking intense tension. But this sister uses her massive breasts to seduce him aggressively. Though he truly cares for Sarina, he can't resist his sister-in-law's overwhelming temptation. While Sarina only allows condom sex, her sister welcomes bareback and creampie without hesitation—the pleasure feels like another dimension entirely. With his girlfriend right nearby, he's powerless to stop himself from thrusting deeper and faster, completely addicted to the raw sensation.