Mix cake according to package directions using 2 whole eggs instead of egg whites. Spoon into 9x13 pan and bake in 350 degree oven. Punch holes with a toothpick all over surface of warm cake.
Mix together cream of coconut and sweetened condensed milk (can add 1 1/2 ounce of rum if desired). Spoon over cake. Sprinkle with a bit of the coconut. Spread thawed whipped topping over cake. Sprinkle rest of coconut over cake. Keep refrigerated. The longer this sets, the better it gets.