Place the Twang-a-Rita Paloma Love on a small plate. Run the lime wedge around the rim of a high-ball glass and dip into rimmer, twisting to coat evenly.
In a cocktail shaker, combine tequila, grapefruit juice, agave, and juice from half a lime. Top with ice and shake until well combined.
Pour into prepared glass and add Shiner Ruby Red Bird. Garnish with lime wedge (or grapefruit slice).
