If using live lobster, parboil first for 5 minutes. Remove and immediately place in an ice bath to stop cooking process. This will also make them cool enough to handle. Remove tails from head. Remove claws from body and pierce/crack to allow steam to escape when grilling.
Cut tails down the middle, lengthwise. Some people choose to go through the hard top (for presentation) but you can also cut down through the softer bottom if it's easier for you. You will want to cut about half way into the meat as well, without going all the way through to create the butterfly effect. *see notes below
Place tails on skewers to help retain a straighter shape and also make flipping easier. If you choose not to skewer them, they will curl.
Mix together butter, sriracha, lemongrass and garlic until well blended. Split evenly into two bowls and put one aside (this will be your dipping sauce).
Heat grill to medium-high, about 475°.
Use a basting brush to generously slather 1 tablespoon butter mixture onto meat exposed sides of lobster tails.
Grill tails, meat side down, for 4 to 5 minutes. (The shell should turn bright orange in color).
Flip tails over and generously slather the remaining tablespoon of butter mixture onto the meat of each tail.
Grill additional 3 to 4 minutes. This will vary according to your lobster tail size so keep a close eye on it and remove from heat as soon as it turns opaque. Overcooking will result in dry meat - no bueno.
While the tails are grilling, lightly toast coconut in the oven. Spread evenly onto a baking sheet and toast under broiler for just a few minutes. Keep an eye on them so they don't burn!
Remove tails from grill sprinkle with coconut.
Serve with fresh lemon wedges and reserved butter mixture.
*Now is the tricky part. Some people can pull the two halves apart with their finger creating a gap for the meat to expand through. This method was very difficult for me and I had a hard time not breaking the sides. If you find this is happening to you as well, you can also simply cut away more shell to create a wider opening. You can also try pre-pulling the meat up through the slit so that it sits on top of the shell, thus ensuring the "look" you may be expecting.You could also just cut the whole lobster lengthwise down the middle. It's easier to prepare, eat and will cook more evenly.
Thai Inspired Spicy Coconut Grilled Lobster from Surf and Sunshine at https://www.surfandsunshine.com/thai-inspired-grilled-lobster-recipe/