My sister started working part-time at a men's grooming salon, but she's been practicing dangerous massage techniques on me—it's insane! (Kuroshima Rei, SONE-623)

My calm and earnest older sister suddenly asked, "Can you practice massage with me?" After applying essential oil all over my body and starting the massage, her breasts touched my cheeks, and she even massaged my groin, just centimeters from my testicles, causing me to get an erection. My earnest sister forgot I was her younger brother and gradually developed more erotic behavior, until finally… Please forget our obscene act of ejaculating.