You will need to heat treat the cake mix before you begin to kill any bacteria. To do this, preheat the oven to 350 degrees Fahrenheit (177 degrees Celsius), line a baking sheet with parchment paper, spread the cake mix onto the parchment paper, and bake for 5-10 minutes. Set aside to cool completely.
In a medium bowl, beat the cream cheese and flavor extract (if using) with a hand mixer until smooth and creamy.
Add the cooled cake mix to the cream cheese and mix until everything is well blended and you reach a firm dough consistency.
Divide the dough into six even portions and place each portion into separate small bowls.
Add a few drops of red food coloring to the dough in one of the small bowls and mix until well incorporated. Repeat the process for the remaining five colors. You should have red, orange, yellow, green, blue, and purple dough once you are finished.
Cover each small bowl with plastic wrap and chill in the refrigerator for at least 1 hour.
Line a baking sheet with parchment paper. Once the dough has chilled, remove the first color, red, and pull apart small 1-inch-sized pieces and lightly flatten them out with your fingers. Place them on the lined baking sheet 1-2 inches apart. Do this until you have used up all of the red dough.
Remove the next colored dough from the refrigerator, orange, and pull apart small 1-inch-sized pieces, lightly flatten it out, and stack it on top of the red pieces. Do this until you have used up all of the orange dough.
Repeat this process with the remaining colors, one color at a time.
Once you have stacked all of the colors, use your hands to roll each ball of stacked dough into a smooth ball, then place it back onto the baking sheet.
Once all of the balls have been rolled, return them to the refrigerator to chill for another 1 hour. Chilling the dough balls will help the layers stick together while dipping in the next step.
Prepare a second baking sheet with parchment paper and set aside. After the balls have chilled, melt the melting wafers in the microwave or using a double boiler.
Remove the dough balls from the refrigerator and place one ball onto a fork. Dip it completely into the melted wafers, then lift the fork up and tap it on the side of the double boiler or bowl to remove any excess coating. Place it onto the new lined baking sheet and immediately add sprinkles on top. Repeat with the remaining balls.
Allow the rainbow balls to set completely for about 5-10 minutes before serving. You can place them in the refrigerator to speed up the process. Keep the balls refrigerated until ready to serve.