I lost my mind and went on a rampage, having sex with my girlfriend's older sister... White Peach Blossom MIAA-609

My girlfriend was waiting in the living room while we prepared for our date, when her older sister didn't return until the morning. Wearing revealing clothing that almost showed her underwear, it was hard to know where to look. Suddenly, her sister started masturbating and teasing me. My girlfriend was important, but the temptation of her lewd older sister was irresistible. Secret oral sex, a surprise attack at night, and increasingly aggressive teasing—I was overwhelmed by tension and a sense of transgression. Although my girlfriend eventually discovered me, I recklessly lost control and ejaculated inside her.