Into a cocktail tin and ice, tequila, Jamaican dark rum, watermelon pucker, strawberry syrup, fresh lemon juice, and citrus bitters. Secure the lid and shake for thirty seconds.
Fill serving glass with ice and fill halfway with strawberry basil soda, top with the tequila and rum mixture.
Garnish with a slice of watermelon and strawberry on a cocktail stick. Add a fresh basil leaf.