For the Cake: Mix and bake cake according to package directions. Remove cake from oven and let cool for about 5 minutes.
Poke holed all over cake with the handle of a wooden spoon, skewer or fork.
For the Drizzle: Combine cream of coconut and rum and mix well. Pour all over cake, allowing it to seep into all the holes and soak in.
For the topping: After cake has completely cooled, combine Cool Whip, sour cream and powdered sugar and mix well. Fold in well drained pineapple and coconut and spread onto top of cake.
Cover cake pan with plastic wrap and refrigerate for several hours or overnight before serving.