Combine the strawberries, cherries, lemon, lime, mint leaves, and simple syrup in a large cocktail shaker. Use the handle of a wooden spoon and mash the fruit together, releasing the juices.

Add in the Bicardi rum. Place the lid on the shaker and shake vigorously for 30 seconds.

Strain into a short glass filled with ice. Top with enough carbonated water to fill the glass. Garnish with a cherry and a strawberry.