In a large bowl, combine pudding mix and 2 cups milk; mix well. Fold in whipped topping. Put in refrigerator for 5 minutes.
I followed most of the recipe found here for the first set of instructions for the chocolate icing:
http://allrecipes.com/recipe/17172/chocolate-eclair-cake/
The second set of ingredients for the chocolate icing was from my grandma's recipe. Her directions say to bring the ingredients to a boil and stir until smooth. Cool before putting on cake. I did not boil the ingredients for long. Once they got to a good boil, I turned it off and let it cool.
Just use one of the chocolate icing recipes.