If the wick doesn't get any fluid, you get the dreaded "dry hit".

It's a god awful, hot, burning, painful experience. With top
coils, you have to make sure to dip and swirl to keep the wicks moistened. Top coils tend to also be a warmer vapor than bottom coils due to the shorter distance to your mouth and less cooling action of the vapor chamber. I prefer bottom coils, but some prefer the flavor of top coils. Try them all and see what you like. Just remember to dip and swirl those top coils!