This is a very good article about allowing kids to set their own physical boundaries, and using the holiday season as a chance to work on that practice:
As a mother, I can relate to the embarrassment that a parent might feel when a child doesn’t want to give a big hug to Grandma when she walks in the door—especially if Grandma has been eagerly anticipating the visit for weeks and months. But through my work teaching personal safety as a Kidpower instructor, I have learned that supporting our children when they set boundaries is a very important practice.
Backing up a child who doesn’t want to be kissed or hugged does not mean that Grandma, or Great Aunt Edna, or Uncle Bob or Cousin Sara are doing anything wrong, but it does demonstrate that touch and play for affection or fun is your child’s choice in all situations. The holidays are a perfect time to work on “boundary setting” with our kids, so they feel confident and empowered as they move through different ages and stages of life.
It’s good to affirm early-on that a child is the one in charge of his or her body, and that their body shouldn’t be used against their will to please other people. That can be hard, and it can hurt some feelings, but it’s an important practice.