This is a single chapter from a longer fic. A friend suggested it might do well as a one-shot. Harry has is being trained personally by Dumbledore, who wants Harry to be comfortable enough around him to refer to him by his first name. Harry can't, so a charm is placed on him that will shock him when he can't refer to someone by their first name. This charm is eventually applied to all at Hogwarts during Harry's training and under this spell they attend the will reading for Sirius.