You only need to prime the coil if it's a new dry coil. You drip
juice inside the coil and wet it good before you put it in the tank and fill the tank to insure the coil is good and wet so it doesn't burn the wick. Once it's wet you shouldn't need to prime it again until you get another new dry coil or maybe if you leave it sitting around empty and the coil dries out again. I'm not sure why you would have no flavor though. Is it possibly a new juice that might be real mild flavored?