My arrogant younger sister practices sex with me by kissing me across the plastic wrap, masturbating, and giving me oral sex! HUNTB-676

My sister has terrible sexual skills and is about to be dumped by her boyfriend, so she urgently summoned me! My sister, who doesn't mind pretending, tried to practice with her brother, but he refused because they're siblings. She insisted, "It's okay to use plastic wrap, right?" She kept practicing kissing and oral sex through plastic wrap, but things escalated further; she even had sex through the plastic wrap! It felt so good that when I vigorously shook my hips, it broke, and I accidentally ejaculated inside her! I thought, "This is terrible!" But then I realized, "After all, going beyond the plastic wrap isn't a good practice."