Cut the 1" foam rubber into the basic shape.

Last year we started with a cylinder shape around a basket ball and a dome top head. 

This year the goal was a dragon shape.  We started with the top of the head and long snout.

Using a hot glue gun we connected the sides of the snout.
 

We added foam for the sides.

The pieces are cut with excess material so we can twist, bend and hold the mask in many ways as we visualize how we want it to look.

Continue forming the entire mask.

The nostrils were formed by cutting the 1" foam in half and them folding the edge over for a smooth rounded edge.  Several sets of nostrils and the ears were thrown out before finding the ones we liked.

Look carefully above the eyes.  There is a piece of foam that looks like two wedge shaped slices of an apple.  This is one of the earlier attempts for nostrils. 
 

After all the foam rubber is hot glued into place, check all the seams.  Add hot glue inside and outside each seam.  Add extra hot glue where seams may tend to tear, like the joint of the jaw, edge of eyes, ears, and horns.

Step 5

Paint the entire mask with liquid latex rubber, (available at art supply stores.)  (Warning -- some people are allergic to latex.)

Let the latex dry and add additional coats.  This mask has three coats of latex rubber.

The final coat was dabbed with a piece of foam to give it a rough dragon skin appearance.
 

Paint the mask using a quality water based tempera.

We made the teeth out of the tines of plastic forks.  The tongue has only one light coat of latex leaving a tongue-like texture.  The lower jaw is connected to the top with rubber bands.  The jaw opens slightly when Max opens his jaw.
 

He later added two plastic red chili peppers for fangs