To sign demand, first, hold your non-dominant flat hand horizontally, facing out to one side of your body. Then do the ASL letter X sign or 'hook' with your dominant hand right beside your non-dominant palm, then touch your hook to your non-dominant palm as you pull both hands in simultaneously toward your body. It is like catching a fish with a hook and reeling it in.
Teach your toddler the demand sign in the context of behaviors that you deem acceptable and unacceptable. It is good to teach this sign along with the more acceptable behaviors of politely asking for something, saying 'please', and thanking someone after they do your toddler a favor.
Teach your child this sign along with other behavior signs, so that your child learns proper etiquette as early as possible.