While my wife was pregnant and giving birth in her hometown, I had unprotected sex with my busty sister-in-law. My beautiful and charming sister-in-law and I had forbidden intercourse. (Usami Midori JYMA-070)

We've been married for three years, and my wife is pregnant. She said she'd go back to her hometown to give birth. I'm enjoying my life living alone, but then my wife's older sister came to help with housework. It was a long time since we'd seen each other, and her voluptuous figure and mature charm were incredibly exciting. Even though I knew it wasn't right, I couldn't help looking at her. Living alone with her made me uneasy. Just then, I caught a glimpse of her masturbating. Our eyes met, and from that moment on…