1. You can use the most direct method, but it can also be the worst. You go and get a hammer and you go straight to whichever coconut is directly on top and smash it straight up. That time the coconut cracks instantly, but this time you need to go and pick up the coconut quickly.
2. Of course there is a gentle way, you can use a rebar and then you use a hammer. You point the rebar directly at the part on the coconut that you want to open, and then you just hammer the coconut to open it up a hollow. Then you just insert the straw and you're done.
3. You can also use a high-pressure water gun, the pressure of this thing is very high, so be careful when you use it. You fix the coconut first, then you point the high pressure water gun at the part you want to open, and then you open it with a spray. It's cleaner this way.
4, of course, you can also use a a more violent method, you take your home drill out. Again first fixed the coconut, and then aimed at the open part of the electric drill, not long a hole is good. Then it's time to enjoy.