My gyaru older sister was embarrassed about sharing a room with me, so she never invited friends over. But one day, her friend suddenly showed up and discovered our sleeping arrangement. The friend was also a gyaru, super cute, and when I caught a glimpse of her panties, I got lucky—my cock instantly sprang a full erection. Shit! She noticed! I panicked, but my sister didn't catch on. Seizing the moment, the friend teased, "Did you get hard looking at my panties, little brother? So cute," then seduced me with a mischievous charm, giving me my first thrilling, nerve-wracking live sex experience. Word spread, and soon another of her friends came over, eyes set on my cock, and right under my sister's nose, I had intense sex with a second girl. Then, catching my sister sneaking glances, I taunted her: "You want it too, don't you?" Provoked, we plunged into a dream threesome with two hot gals. From that day on, my sister returned to her sweet old self—and taking advantage of our shared room, we've been fucking nonstop every single day.