Take all of your utensils and glasses that you will be using to make this great cocktail and wash everything thoroughly. Make sure that you also clean or wash the work surface that you will be using to make this cocktail in your kitchen.
Take a large plastic bowl and place eight wedges of the orange, coarsely chopped fresh ruby red grapefruit and caster sugar in it. Remember you can add or subtract any of these ingredients according to your personal taste.
Carefully pound the mixture with the help of a rolling pin until slightly crushed. Remember to be very careful while pounding the ingredients as you do not want to smash your finger.
Distribute the mixture equally among the four serving glasses. Depending on the size of your serving glasses you can easily decide how to divide it up accordingly.
Top each of the glasses with crushed ice according to your personal taste. You can now pour white rum over the glasses along with limo cello and chilled tonic water. Make sure that you properly balance each ingredient so that it does not overpower the smooth taste.
Garnish the glass with a slice of lime or orange if you want and serve immediately to your guests. You will see a big smile on their faces as they enjoy this delicious cocktail. Remember that this cocktail is quick and simple to make so you can always put it together on short notice or even as your guests sit around and mingle.