My Stepmom is a Futanari

You're a college student on holiday, so you decide to give your single dad a visit. After a phone call you are surprised to learn that he's met a special someone. Soon after arriving home, your dad asks for your blessing to marry his amazing girlfriend -- making her your stepmom. After unforeseen circumstances arise, you find yourself alone with your soon-to-be stepmom and she has a special surprise -- just for you.