Saki 36 years old, remarried to a distant husband and had a new son. Her son, Yuuki, is a little mother's boy, probably because he had a long family with his father. He brings her back from school. She takes tea to the front of her room, and Saki peeking through her gap witnesses him failing her first sex. After that, Saki comforted her depressed son ... "It's absolutely secret to my dad." A sex practice that her mother gently teaches her son. Motherhood of Saki Mama, who is darker than her blood ties! !!