A Secret That Must Not Be Known 3 (Pixiv Fanbox)

Hatsuko is often away from home on business trips. Young Kokone must have missed her mother very much. As a result, she became overly spoiled by her mother when she returned from business trips, and this came out in the form of babyish behavior. It became a conditioned reflex, and she regressed when she saw her mother returning from a business trip.