I've been close friends with my childhood friend Yuri for over ten years. She'd always come over to my place, joking around and hanging out like a guy buddy. Recently, her best friend Uno-chan started visiting too. Popular in class, her presence gave me a subtle sense of superiority and excitement. Before long, my house became their regular hangout spot after school. One day, both our parents went on a trip, leaving us to hold a study session at my place. Uno-chan joined us, and the three of us studied casually while chatting. After finishing, we collapsed onto the futons, talking freely when suddenly Uno-chan asked, "Have either of you ever had sex?" That single question shifted the atmosphere—triggering what came next. Yuri admitted, "I've done it with a senior two years above me," and Uno-chan suggested, "Why not study sex too?" Surprised, I replied, "Huh? What are you talking about?" But she pressed, "You'll do it with me too, right? For sex practice?" Caught in the moment, Yuri chimed in, "That's not fair—I'm joining too!" Soon, all three of us were deep in conversation about sex. Things escalated quickly, and during each break, I devoured their smooth, glossy big tits, ultimately indulging in intense, animalistic threesomes like we were in mating season.