Continuity mistake: In their first scene, Andy's mom wants him to go out some. She waves the phone at him holding it in two different ways (index on the top right corner or at the middle of the right side). (00:07:20)

Continuity mistake: On top of the ladder, the Xmas lights wrapped around Shane change between shots repeatedly. (00:38:00)
Answer: I wouldn't read into it much more than just a joke: Chucky heard that joke earlier when the kids in the street were trying to make him do things for their cell phone cameras. So he just re-used it later as he often does in the movie.
Sammo ★
It was a joke that some kid said when he had the Chucky doll.