I still remember how to stop an infant from choking from the babysitting course I took when I was 12.
If you mix table food with 9 1/2-month old, sooner or later, she will try to stuff more in her mouth than she can actually eat. Lindsay chose sooner. She stopped breathing. She turned blue. I picked her up and gave 5 sharp blows between her shoulders, and the offending piece of sweet potato cartoonishly flew across the room.