Before doing anything else you should carefully wash the work surface where you plan to make this fabulous slushie. Be sure to also wash your hands and all of the utensils and other items that will be used to make this recipe. Remember to also wash all of the ingredients as well. You might want to make it a habit of keeping everything clean before making any sort of food or beverage in your kitchen.
Cut a peeled, seedless watermelon into two inch chunks and freeze it in a Ziploc bag for at least six hours. You can also freeze the watermelon chunks for overnight. Be careful while cutting the watermelon as you will want to hold it firmly so that it does not slip around your work surface. Remember to observe all safety precautions when handling a sharp knife.
Put the frozen watermelon in a blender. It is up to you as to how thick you want your slushie to be. If you want it a little less thick then you can reduce the amount of watermelon that you use.
Add six ounce lemonade concentrate, six ounce orange juice and 4 ½ cup of water. To reduce the level of sourness you can always reduce the amount of lemonade.
Blend the mixture well until it is smooth; stopping once to scrape down the sides of the food processor. You will want a nice smooth texture to the mixture so be sure to check the consistency while blending. Try not to over blend the mixture as it can become thin. Make sure that the lid of blender or smoothie maker is tightly closed when mixing all the ingredients.
Pour the mixture into serving glasses after garnishing it with watermelon slices. You can also serve the chilled slush out of a watermelon used as a punch bowl. Remember it is entirely up to you as to how you want to serve and garnish these fruity slushies.