"Wait, Amet! I'm not...no..." Mistaking her for my girlfriend, I immediately pierced my twin sister from behind (super serious and simple)! I misunderstood, and then ejaculated... HUNTA-824

My girlfriend has a twin sister who's calm, serious, and has nothing to do with sex! I completely mistook this proper sister for my girlfriend (the older sister) and immediately had sex with her from behind! Without realizing it, I used my raw penis to make her ejaculate again and again. Midway through, I realized she wasn't my girlfriend, but my sister, and desperately apologized!! I thought this was dangerous, but the ordinary twin sister, now in heat, started shaking her hips and ejaculating again and again! She suddenly transformed into a more lewd and obscene woman than her sister, actually engaging in sexual acts with her (the older sister) that I absolutely wouldn't allow!!