Big glass of ice.
One can of Diet Coke.
1/2 of a lime.
1-2 pumps of sugar-free Coconut Syrup (Priate O's and Orson Gygi carry this syrup).
Fill up your glass with ice. Squeeze in the lime. Pour in your Diet Coke. Add 1-2 pumps of the Coconut syrup. Stir with a straw and ENJOY. Very refreshing.