In a collins glass, add 2 tsp white sugar, 1 whole sprig yerba buena, juice from half a lime. Muddle mint and dissolve sugar. Add 1 oz soda. Stir to dissolve sugar more. Add 1.5 oz white rum, lots of ice (not crushed). Top with soda water, and another whole sprig yerba buena for garnish. [Good luck getting Yerba Buena outside of Cuba, guajiro.]