Some add an egg white to the mixture for texture. Perfect with a date. The milk should be really hot for this one. Shake very well until the drink is full of foam. Pour into a coffee mug and drink hot.
Orange bitters are available at the larger liquor stores.
Do not substitute Angostura. Shake with ice, pour into goblet or large wine glass, ice and all. Garnish with mint, pineapple and the like. If out of dark rum, white will do. In this case, strain and drink as a cocktail.