When an infant is choking and is responsive you should immediately call 911 and start giving the back blows to help get whatever it is out of the infants throat when they are choking.
You give a responsive infant 5 back blows when they are choking and the 5 back blows you give the responsive choking infant should be done between the infants shoulder blades on their back.
Continue giving the back blows to the infant if they are still choking and get emergency help and an ambulance on the way but continue with the back blows on the responsive infant.
It's important to try and get the infant to stop choking so they can breath.
Do not wait for the ambulance or other help and do it yourself while waiting as seconds count when the infant is choking.
Everyone who has kids or babysits or takes care of kids and infants should know how to do the back blows, abdominal thrusts and CPR.