In a cocktail shaker filled with ice combine the tequila and grapefruit juice. Shake well until the mixture is chilled.
2 ounces silver tequila, 1 cup fresh grapefruit juice
Fill two rocks glasses with ice. Strain mixture evenly into each glass.
Start by adding 1 teaspoon of grenadine to each glass. If the red isn't vibrant enough, add 1 more teaspoon. Add a wedge of grapefruit as garnish on the rim of the glass.