I was so tempted by my sister’s unprotected seduction that I gave in and had sex with her right away! I was given an erection by the temptation of her panty show. Natsu Igarashi

お姉ちゃんの無防備な誘惑に負けて即ハメしたら豹変！ 誘惑パンチラ全力アピールで勃起させられまくったボク。 五十嵐なつ

Also known as FSDSS-492

I had an older sister due to my parents' remarriage. His sister-in-law is a cool and beautiful woman with an outstanding figure, but she was defenseless and often flashed panty shots. One day, she finally reaches the limit of her patience and inserts the panty shot into her beautiful butt, pistoning hard and ejaculating. I thought his sister-in-law would get mad at me, but the next day she started showing me her panty shots and seducing me...