Turn the burners of a gas grill on to medium-high. If you're using a charcoal grill, fill a chimney with briquettes and light them. Once the coals are hot and lightly ashy, dump them on the grill grate. While the grill is heating, put 8 tablespoons (112 g) of softened salted butter into a bowl and mix in 2 tablespoons (6 g) of chopped chives, 1 tablespoon (2 g) of chopped fresh tarragon leaves, 1 minced clove of garlic, 1 dash of hot sauce, and freshly ground black pepper to taste. You can cover the bowl with a plate or plastic wrap and set it aside at room temperature while the lobster tails cook. Get out 4 thawed lobster tails and insert a metal skewer through the length of each tail. Then, brush a little olive oil over the meat of each lobster tail and sprinkle them with salt according to your taste.  The skewers will prevent the tails from curling as the lobster cooks on the grill. The olive oil will stop the lobster tail meat from sticking to the grill. Lay the tails meat-side down on the grill and cover the grill. Cook the tails until the shells turn bright red. At the halfway cooking point, use tongs to carefully flip them over and brush some of herb butter onto the meat. The meat should be completely white and tender once it's finished cooking. Use tongs to transfer the tails to a serving plate. Set out wedges of fresh lemon and the herb butter that you mixed earlier.  The grilled lobster is great served with grilled vegetables, such as asparagus or peppers. Refrigerate leftover tails in an airtight container for up to 4 days.

TL;DR in Vietnamese:
Chuẩn bị bếp nướng than hoặc bếp nướng ga với lửa to vừa. Trộn bơ, thảo mộc, tỏi, tương ớt và tiêu trong bát. Xiên đuôi tôm hùm vào que và phết dầu ô liu. Nướng đuôi tôm hùm khoảng 9-10 phút. Lấy đuôi tôm hùm ra khỏi vỉ nướng và dọn kèm với bơ thảo mộc.