First, mix the scallions, coconut milk, fish sauce, sugar, and salt in a bowl.
Next, dip all the corn in the sauce and place on a medium heat grill for five minutes. Turn the corn every minute or so to grill all sides.
Now, dip the corn again in the sauce and grill five more minutes turning every minute to grill all sides.
Finally, dip in the sauce one more time and then place on the platter.