One day, while he was living happily and peacefully after getting married, his wife's sister came to the house while he was away and suddenly asked for his dick! He refused in words, but his lower body reacted more than ever to her request, and it got hard! He was in a situation where he was extremely nervous that his wife might find out. Even between real sisters, their sexual preferences are so different. If he ejaculates inside her pussy, he should be able to cover up the evidence of his affair...