- Place mint leaves, the lime juice and pulp, and the sugar in a medium pitcher.
- Use a muddler to crush the mint and blend the juice and sugar.
- Add the ice, rum, watermelon juice, and club soda.
- Stir, taste, and add more sugar or lime to taste.
- Add a few diced watermelon if desired and garnish each glass with mint and a thin slice of watermelon.