How to Make It
Stir together rums in a jar with an airtight lid. Seal and store at room temperature up to 1 year.
To make 1 drink, squeeze juice from lime halves, and reserve juice for another use. Combine lime halves and rum mixture in a bowl. Muddle well to release oils and a bit of the remaining lime juice; remove and discard lime halves. Fill a highball glass with ice; fill three-quarters of the way with cola, and top with 6 tablespoons rum-lime mixture. Garnish with a lime wedge and an upside-down unopened mini bottle of Bacardí.