What gets liquid in your mouth is when you overfill the cart and liquid flows into the atty, and then gets carried by the airflow into the air vent to the side(s) of the liquid holder in the cart.
If you don't tip the cigarette up too high (keep the tip lower than the mouth end) and breathe gently (taking some air in through the sides of your mouth, not sucking only through the mouthpiece), you can avoid getting liquid in your mouth even if the atty's somewhat flooded.