Teach your baby or toddler the fat sign when describing animals, people, cartoon characters, and so on. It is important though to underscore that this modifier -- like any of the other describing words -- is not meant as an insult. Teach it rather as an objective term of observation.
Teach your toddler this sign in conjunction with other personal modifiers pertaining to not just size or shape but height, age, and coloring as well.
Get all four volumes of Baby Signing Time...