Step-By-Step Instructions:
1. In Photoshop, open a photograph of a person with their mouth open.
2. Goto Filter > Liquify.
3. The Liquify box will appear. Under Tool Options, select an appropriate sized brush. One that is not too big for the mouth.
4. Using the brush, click and push the bottom portion of the mouth and jaw downward so that it looks stretched and cartoonish.
5. When you are done, click OK.
6. You should now have your cartoon stretched mouth.
