The rum coco was made sort of famous in the U. S., and hip in some quarters, like my house, by the Tennessee Williams play and film Night Of the Iguana, in which it's presented as the specialty of the house at the Costa Verde inn on the west coast of Mexico, where the story is set.
In fact, the rum coco is one of the most popular mixed drinks among locals south of the Rio Grande and around the Caribbean, any place where rum is popular, though generally not considered fancy enough for tourists.
It's made with coconut water, the almost clear juice of young coconuts, not coconut milk, the white juice of mature coconuts, which is thicker and sweeter. Coconut water is a miraculous drink all by itself, low in fat with no cholesterol and more potassium than most sports drinks, and can be used in a pinch as a substitute for blood plasma in surgical operations, delivered intravenously.
My friend Jae recommended it to me as a healthier alternative to the sports drinks I consume regularly out here in the Mojave Desert, to keep hydrated in the extreme dry heat. However, it didn't take me long to realize that it's sort of a crime to drink coconut water without a healthy shot of rum in it.
Traditionally the rum coco is made with a light amber rum, some ice and nothing else, but I like a slice of lime in it. Vita Coco is the best known brand of coconut water but can be hard to find and tends to be a little costly. I have a small case of it delivered to my home every month via Amazon, which offers a good deal on such an arrangement.
What a happy day it is when that small case arrives, and how quickly it vanishes in nights of tropical dreaming. After two rum cocos, you can hear the waves breaking on the shore nearby, even when there is no shore nearby, and the rustle of the palm fronds sounding just like rain. A voice whispers in your ear, “Go on, fall apart,” and you fall apart, your molecules dispersing in the humid night air. Soon there's nothing left of you at all — nothing but the scent of flowers on a breeze coming in from the ocean.