I eat young coconut weekly. I have had it in many other countries and buy them here in the US in the supermarket. Never had a bad experience.
I cut the top off with a serrated knife, using it like a saw (there is a nack to finding the right spot).
Insert a straw, sip off a 2-4 ounces of the water.
Add 2-3 oz Gosling's or Sailor Jerry.
Squeeze in a wedge of lime.
They go down fast and easy on a hot summer night whilst singing "you put de lime in de coconut and drink it all up..."
'88 C&C 30 MKII