Spray a 9x13-inch cake pan with non-stick spray. Prepare cake according to package directions with the vegetable oil, eggs, water, and coconut extract. Bake 25 to 27 minutes.
Remove cake from the oven. While still hot, using a fork or skewer, poke holes all over the top of the cake.
Mix cream of coconut and sweetened condensed milk together. Pour over the top of the still-hot cake.
Let cake cool completely then frost with the whipped topping and top with the flaked coconut. Store cake in the refrigerator.