1 can (12 oz) frozen limeade concentrate (thawed but still chilled)
12 oz tequila
12 oz water
12 oz beer (Corona is prefered, or a lime flavored beer)
Pour limeade, tequila, water, and beer into a large pitcher. Stir until well-blended. Add plenty of ice. Adjust with additional water, if needed.
Garnish with lime slice as seen above, if you like.