In a resort area, a couple was approached and it turned out to be siblings. The sister was a slut who changed men frequently, and the brother was a virgin. A game of baseball was proposed, where if the brother couldn't get an erection from seeing his sister naked, he would win a prize. The siblings played deep kissing, vibrator games, and other erotic pranks. They were already used to seeing each other naked, so it was easy for them to get excited. As they played, the atmosphere became more and more intense. The brother was fully erect. They were already aware of each other. So, let's just be "man" and "woman"! Here is the documentary of the crossing of the line between the outgoing sister and the introverted brother!
