I was dating the younger sister of my childhood friend's sisters, and my older sister, who actually liked me, was insanely jealous. She was unbraced and used breast-related tactics. (Yumeno Aika SONE-640)

If I had confessed sooner, I wouldn't have hurt anyone... Aika (the older sister), Risa (the younger sister), and I were childhood friends, always together throughout our school years. I liked Aika, and I was sure she liked me too. But because we were too close, nothing ever progressed until we were almost thirty. I often went to their shared apartment, and while chatting with Aika, reminiscing about our school days, she said, "You're still clinging to past glories, that's why you can't find a girlfriend, right? You're so old." Why would she say that about me...? I angrily retorted, "You don't have a boyfriend either, it's because of your personality that you're single!" Risa noticed our argument and comforted me. I confessed to her, and we started dating... Aika, seemingly to get revenge, started seducing me with her exposed breasts. I always thought her breasts were big, but I didn't expect them to be this big... Her nipples were showing... "Risa has no sexual experience, I don't want to hurt her, let's practice sex?" Jealous Aika desperately wanted to win me back, and even with Risa nearby, I couldn't resist the temptation and had sex with her multiple times. "Do you really like Risa?" "...I've always liked Aika." Why didn't I say that sooner...? I confessed to Risa: "I knew it... If only I had been honest from the beginning." Risa stormed off, but she understood me, and we finally became lovers...