THE SUMMER SOCIAL Ingredients $ 1.5 oz Mailroom Vodka $ 1 oz Watermelon Syrup $ 0.5 oz Lemon Juice $ Grapefruit Soda Directions $ Put all ingredients into a cocktail shaker, except for the grapefruit soda. $ Shake and strain the cocktail into a Rocks glass. $ Top with grapefruit soda. $ Garnish with a watermelon slice and fresh mint leaves.