Oyako no Himitsu ~Tsuma ni Ienai Oyako no Kankei~

It's Ryoutaro's daughter Risa's birthday. He buys her a gift from a department store but she seems more distant and aloof than ever. He wakes up to find himself completely enveloped in his daughter's vagina. She's been waiting for her birthday to give her virginity to him and finding him asleep was the perfect opportunity. Now she wants more and more from her father while keeping their forbidden relationship a secret from his wife.