Add both rums, coconut rum, triple sec, lime juice, pineapple juice, and orange juice to a cocktail shaker filled with ice.
Shake for 10-15 seconds until well chilled.
Strain the mixture into the prepared Collins glass.
Add a splash of grenadine and top with cola.
Stir gently with a bar spoon to combine.
Garnish with an orange slice and cherry.
Notes
The drink should have a layered amber-to-red color when properly made.Fresh juices make a big difference in taste compared to bottled versions.Store unused fresh juices in sealed containers in the fridge for up to 3 days.For a less strong version, reduce each alcohol portion to 1/2 oz instead of 1 oz.This recipe serves one person and takes about 5 minutes to make.