Kinpatsu Tarou Monogatari

The story is about a blonde hair blue-eyed boy named Tarou who grew up receiving his mother's love in a nature-filled area called Ashukurayama. Recently, Tarou has been feeling a warm sensation in his lower abdomen when he takes baths with his mother or wrestles with his beast female friends. He consults with the elder of the mountain, Tamamo, who tells him that it's natural for boys to be attracted to girls' feminine energy. That night, when Tarou takes a bath with his mother, he gets aroused and his mother takes it upon herself to guide him through his first sexual experience. The next morning, Tarou finds himself in a world that has transformed from innocent picture books to adult erotica.