Care and Feeding is Slate’s parenting advice column. Have a question for Care and Feeding? Submit it here . Dear Care and Feeding, My sister-in-law and I have three children around the same age and have been trading off childcare for years. The problem is that my 13-year-old niece, “Erin,” has hit her terrible teens with a vengeance. She is a big girl and a bigger bully. She thinks nothing of getting physical with any of the other children when she wants something. She will push, pull, and rip