To make watermelon cup: cut a small slice off the bottom so it sits flat on your surface. Cut off the top 1/3 and with a melon baller, scoop out the flesh and freeze the watermelon balls overnight. Wrap your watermelon cup in plastic wrap and refrigerate overnight. To make slushie: Combine Torani, frozen watermelon, and water in a blender pitcher and blend until smooth. (add alcohol at this point if making a boozy slushie) To assemble cup: Pour slushie into watermelon cup. Garnish, Serve & Enjoy!