Fill a tall glass two thirds full with ice cubes. Pour the cola over the ice and allow it to chill for a minute or two.
Add about 5 ice cubes to a cocktail shaker and add the gin, vodka and rum, along with the dash of Cointreau. Squeeze the juice from the slice of orange and the limes in as well. Include the skins of the fruit. Finish with the drop of orange blossom water and shake well