Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9- inch round cake pans.
In a large bowl, combine the cake mix and instant pudding. Add the eggs, water, 1/3 cup rum and oil, mix well. Fold in the 1 cup coconut and spread the batter evenly into the prepared pans.
Bake in the preheated oven for 25 to 30 minutes, or until a toothpick inserted into the cake comes out clean. Allow to cool.
To make the filling and frosting, stir together the second package of pudding and the pineapple, including the juice. Fold in the cool whip and more rum if desired. Fill and ice cake. Chill until serving time.