Add the watermelon and lemonade in a frosty glass and stir. Pour the beer over top, squeeze in a lime wedge and garnish with another. Serve with a slice of watermelon!
To make fresh watermelon juice, slice out all of the fruit from the rind and add it to a blender or a food processor. Blend until completely pureed. Pour the watermelon puree over a fine mesh sieve into a large measuring glass or bowl, pressing with a spoon to get every last bit of juice. Store in a sealed container in the fridge.