For this exercise, use Goldfish crackers. 

Make sure you breathe through your nose. 

Place the Goldfish on the central part of the tongue and place the tongue on the N point. Then create suction with your tongue to crush the Goldfish on the roof of your mouth. 

Keep your mouth closed and swallow as needed without letting go of the goldfish. 

Repeat for a total of 10 to 20 Goldfish once melted. 

No part of the tongue should protrude beyond the upper teeth, and all parts of the tongue should lie on the roof of the mouth.