Start by teaching the child to blow a ping pong or cotton wool ball across the table with their mouth. You could also ask the child to try and blow a ping pong ball across water in a bowl.
Then try the same activities, but this time ask the child to blow through his or her nostrils. If this is difficult for him/her, hold a tissue in front of the child’s nose and ask them to blow to make the tissue move. Encourage with verbal cues, such as “blow hard!”.
Demonstrate how air comes out of your nose by blowing against a mirror to show how it mists up. Practice with each nostril.
Put a feather in front of the child’s nostril so that they can see it moving. When he or she blows say “take a big breath, and close your mouth”. You could get them to chew a sweet but keep their mouth shut while blowing.
Ideas have been sourced and adpated from the Dyspraxia Association, New Zealand.