Prepare an outdoor charcoal grill, filling the fire bed 6 to 8 inches deep. Allow the coals to become ash covered. Shake excess water from the seaweed if necessary and scatter half of it directly over the coals.
Dispatch the lobsters (see below) and place them on top of the steaming seaweed. Cover the lobsters with the remaining seaweed and press down on it to force both lobsters and seaweed into the coals.
Cook the lobsters about 45 minutes, sprinkling the seaweed with 1/4 cup water every 10 minutes to keep it moist. The lobsters are done when the shells are bright red.
Remove the seaweed with the tongs to a large platter. Split the lobsters, place them on the seaweed, and serve.
Dispatching a lobster: to kill a lobster instantly, place it on your cutting board (head away from you, tail facing) and insert the tip of a large chef's knife just behind the head. To avoid muscular contractions, you can put the lobster in the freezer for a few minutes beforehand.