In a pot over low heat add the condensed milk, butter, and the unsweetened cocoa. Mix everything together until it gets thick (for 10-15 minutes).
Cover the bowl with butter then pour the mixture into it and take it to the refrigerator. Once cold, take small portions of the mixture and shape them into a ball, as if they were truffles.
Put the chocolate sprinkles in a plate and decorate the ball until they are covered.
