2 oz Cranberry Sauce-infused rum (or spirit of your choice)
1 oz fresh lime juice
3/4 oz orange liqueur
2 dashes bitters of choice (optional)
2 oz tonic water
Add all ingredients except the tonic water, along with a large handful of ice to a cocktail shaker. Shake vigorously until the shaker is very cold, about 10-15 seconds. Pour into a tall glass with ice. Top with the tonic water, and give it one gentle stir.