Dai, who is ignorant about sex, spends his days in agony, not knowing how to release his erect cock. At that time, he takes the plunge and consults his friend's mother, Momoko, who is always kind to him. Momoko, who knew his troubles, was confused, but she secretly taught her sex. Then, Dai, who has lost himself in her first stimulation and pleasure, pushes Momoko down with excess momentum. Momoko shook her hips like a monkey and continued to climax with his cock that stimulated her vagina.