Tsubasa had a good relationship with her husband's stepchild and lived a happy life. The only worry threatening this happiness was Tsubasa's own outrageous sexual habit, which made her instantly horny and lewd when she saw a big penis. If her bad habit came out, her family would fall apart... Tsubasa carefully hid her sexual habit and played the role of a good mother. But one day, she accidentally found out that her step-son had a big penis...