Bake cake according to directions. Cool. Combine cool whip, sour cream, sugar and coconut. Cut the cake to make 4 layers and spread mixture between each layer. Then cover top and sides with remaining mixture. If you like a lot of cool whip, you may add another carton to help frost the top and sides. Garnish if you wish with cherries and nuts. This is a good recipe to experiment with by adding different things to the cool whip. For instance, well drained crushed pineapple, cherries and nuts.