ANSWER:
DO NOT PANIC, BUT START COUGHING REPEATEDLY AND VERY VIGOROUSLY.
A DEEP BREATH SHOULD BE TAKEN BEFORE EACH COUGH, THE COUGH MUST BE DEEP AND PROLONGED, AS WHEN PRODUCING SPUTUM FROM DEEP INSIDE THE CHEST.
A BREATH AND A COUGH MUST BE REPEATED ABOUT EVERY TWO SECONDS WITHOUT LET-UP UNTIL HELP ARRIVES, OR UNTIL THE HEART IS FELT TO BE BEATING NORMALLY AGAIN