Does your body when drinking juice automatically stop the liquids from going into your lungs?

Epiglottis. Yes. The epiglottis is a cartilage like flap that overlies the trachea ( windpipe) and helps prevent food and liquids from entering the lungs. We have all gotten choked on liquids in the past and had a spasm of violent coughing - this is when some liquids get around the epiglottis and enter the trachea. A reflex expels the liquids so they don't enter the lungs.