Milk can add a soft and creamy consistency to drinks and cocktails and is often used in dessert drinks such as White Russian and Mudslide. However, it is important to be aware that the milk can separate when mixed with acidic ingredients such as lemon– or lime juice. To prevent the milk from separating, you can either use condensed milk or add the sour ingredient at the end and gently stir it in so it doesn't mix too hard. It may also be a good idea to use fresh milk and keep it cold until you need to use it in your drink.