Railed by My Daughter's Boyfriend

Yukako Kano is an ordinary housewife with a loving family. When her daughter Sae brings a boy over for the first time ever, Yukako gets curious and takes a peek through Sae's open door. Sae's boyfriend, Kengo, looks like a delinquent punk, but he's actually surprisingly earnest and caring; he gently pushes back on Sae's sexual advances, telling her that he wants to treat her right and take their relationship one step at a time. Yukako can't help but be impressed by Kengo's sincerity—until she sees the two of them getting down and dirty the very next day, and finds herself impressed by Kengo's size instead. Unable to get Kengo's massive cock out of her mind, Yukako ends up guiltily shlicking off in the bathroom to the sounds of Kengo and Sae having sex right next door. While she's still coming down from her climax, Kengo walks in on her and suggests something that'd feel even better...