Place all the red gelatin in a large bowl. Pour in 3 cups boiling water; stir to dissolve gelatin, about 3 minutes. In another bowl, sprinkle 4 envelopes unflavored gelatin over 3 cups cold water. Let gelatin sit to absorb water, then stir to combine. Pour clear gelatin into red gelatin, and stir to combine. Pour mixture into a 9 x 13-inch baking pan, and refrigerate until set, about 2 hours.

Dip lip-shaped cookie cutter into hot water, then cut out shapes from set gelatin. To make it easier to remove "lips" from pan, place bottom of pan in hot water for 5 to 8 seconds, then remove the cutouts with a thin spatula. Pipe outline of lips using pink decorating icing.