CE2s always have to be tilted, so that the juice flows toward the cup, which is near the mouth end, every couple puffs, in order to keep the wicks saturated. This is especially important, the higher the VG percentage in the juice, because it's thicker. It needs a little help from gravity in order to get the juice to the coil. I've been using CE2s for over a year, and love them. But I use 70PG/30VG juice.