Married for 23 years, Mitsuo and Suzuhana are still a happy couple. Even though their son Yuji has grown up, they still take baths together every day. In the bath, Mitsuo, who has a strong sexual desire, sucks Suzuhana's nipples with a lovey-dovey look, and his mother becomes just a female in the bath, forgetting to suppress her voice as she sucks Mitsuo's cock. Not knowing that his parents are making out and mating in the small bathroom, Yuji gives them "bathroom comfort goods" as a gift for their wedding anniversary...