There's no need for a hole because there's no pumping...that's the best part. By venting the bottle it's no longer a closed air system and the juice stays up the tube. When you draw on the cart, juice is pulled into the cart filler. If I lay it down for a few hours and need to "charge" the cart, I draw a few times without pressing the button....and then vape till the bottle is empty. Then, I open the box, refill, and back to vaping. Nothing wrong with a bottom feed; I just don't like to pump.