While cake is still warm, punch holes all over it. Mix the condensed milk and cream of coconut, and rum if using, and spoon slowly over cake. (It takes some time to soak in, so be patient) spon pineapple and its juice over cake. Refrigerate for several hours or overnight. Before serving, cover with whipped cream or topping and sprinkle with coconut. Nutritional info per serving: 593 cal; 5g pro, 80g carb, 29g fat(44%), .3g fiber, 52mg chol, 358g sodium