VENX-215 Suddenly, my wife's sister barged in and I was kept on edge for a whole night and day

While my wife was visiting her parents, her sister Kunatsu came to check on us. We were delighted to have a guest after so long and enjoyed chatting. However, when Koji went to take a bath, the situation changed. 'Please don't come in, Aunt!' Despite his protests, Kunatsu insisted on washing his back, and they ended up soaking together in the bathtub. Seeing Kunatsu's unguarded and beautiful body in front of him, he felt desire rising despite himself...