Here, 'shape' is a verb. It tells you to move your lips, tongue, cheeks etc. into a certain position (probably to say a vowel).
'Properly' is an adverb describing 'shape'. It means the same as 'correctly'.
May 19, 2013
What is the context? Usually this would be used to describe how you move and position your lips. When I say "O" my lips are shaped like a circle. When I pronounce "t" they are flat and don't move much.