When my son was a little boy, I used to play a game with him. I would say, "Who are you, little boy, and what are you doing here in my house? Who do you belong to?"
At this point, I would begin to list off people we knew, our neighbors, friends, etc., and he would laugh and squeal and reply, "No mommy," each time. After going through four or five people, I would stop and say, "Oh, I know! You are my little boy, and mommy loves you very much, and you belong here."