Musuko no Yome no Yuuwaku Ecchi ~Otou-san, Watashi Mou Gaman Dekimasen!~

One night, Daisaku accidentally witnesses his daughter-in-law, Kaori, pleasuring herself. They make eye contact and return to their rooms awkwardly. Later that night, Daisaku wakes up to a strange sensation and finds a woman performing a sexual act on him. To his surprise, it's Kaori. She explains that she couldn't resist anymore because of Daisaku's passionate activities every night.