I did this the other day by accident and realized that I got a much better vape and throat hit.

When topping off your cart, push the cartridge back with the atomizer and then use the plug to push it in just a little bit more making sure that it doesn't come to rest with the end of the mouthpiece. Using the atomizer to push back the cartridge creates an indentation into you cartridge material. I couldn't believe the difference and I am getting less juice in my mouth, which is a plus.