[Imomuya Honpo, Singleton (Azuma Yuki)] A Mistake was the Start of Secrets 2 [LoliAce]

A teacher hoping for easy days after transferring to a rural school gets caught watching a twintailed student touch herself in the infirmary, and her accusation becomes the leash she keeps him on. What starts as one girl's blackmail quickly spirals as two more classmates stake their claim, turning his punishment into a teasing three-way contest over who can make him break first. Between striped stockings, gasped dares of who will lose, and bodies far too bold for their small frames, his quiet country posting becomes the least restful decision he ever made.