Scoop ice cream into 8 small balls and immediately roll in coconut. Place on wax paper lined baking sheet, freeze until ready to use. Whisk cocoa into milk in a large saucepan. Stir in rum, if desired, cream of coconut and coconut extract. Bring to a simmer over medium high heat. Pour into 8 large heat-proof mugs. Float ice cream balls in cocoa. If desired drizzle each ice cream ball with chocolate sauce and top with a cherry.