Keep in mind that this is not a drink you'll likely be able to order at a bar. It's a traditional drink for the Feast Day of Saint John. It's carries a kind of rustic flavor to it that always brings a smile to my face.
To make Leite de Onça, you need milk, condensed milk, cachaça, and chocolate liqueur.
Begin by taking a container to mix the ingredients. You can make this drink in rather massive quantities if you want, so I'll list it by ratios. Begin by mixing 1 part milk, and 1/2 part condensed milk. Mix them until they've blended together. Then add one part cachaça, and chill it. The drink is served cold. Right before your ready to serve the drink, add 1 part chocolate Liqueur. Then pour it into a mug. If you choose to add a garnish, sprinkle either Cinnamon or chocolate powder. Once the drinks have been served, go out and enjoy the summer night.
As usual, if you don't have cachaça, or don't like the taste, you can replace it with rum. The most popular variant replaces the cachaça with Vodka. This version is popularly called Tiger's Milk. Rawr.