Now you need to move your tongue into the correct position. Using your fingers, carefully press your tongue back into your mouth, and gently press its tip downwards. You should end up with a ’curve’ formed from your tongue. Your fingers should be no more than about one quarter inside your mouth.
Breathe out through the air passage that’s formed in your mouth. If it feels like the air is passing only over your lower lip, then you’ve done it correctly. If it seems to be passing by your upper lip as well, you need to reduce the size of the air passage using your fingers.