Saki is 40 years old. With a bright, unshakeable, and open personality, she has always been close with her son, Makoto. They talk about everything, and she has always given him advice on delicate matters like romance, sexual worries, and sex. One day, Makoto returns from a date feeling dark and depressed after failing his first sexual experience with his girlfriend. Seeing this, Saki suggests, "Do you want to practice sex with Mom? You can do it anytime without hesitation." And so, the mother and son begin their secret lessons... "This is the pussy, this is where you put your cock." "Yes, swing your hips more... Makoto-chan, you're doing great." An immoral sexual encounter between mother and son, losing his virginity right at home!!!