In Guys and Dolls, Jean Simmons and Marlon Brando drank their milk punch by Havana moonlight, but it is more commonly served at brunch or as a morning-after pick-me-up. You can vary the amount of sugar to taste, but keep in mind that unlike daiquiris or Mai Tais, milk punch should be relatively sweet.
Fill a shaker with ice. Add 1/2 cup milk, 1/4 cup white rum, 2 tablespoons dark Jamaican rum, 1 tablespoon sugar and 2 or 3 drops pure vanilla extract. Shake well and strain into an old-fashioned glass or empty coconut shell.