We had two different practice dummies that filled the various roles of an adult, youth and infant. One of the key things you are supposed to do before jumping right into CPR is to test the person for responsiveness first. There are various ways to try and stimulate a response out of them before you see if they are actually breathing and begin compressing their chest.
We were told to test the baby for responsiveness, so I picked it up and shook it.
Apparently, that is not the correct way to test a baby for responsiveness. Now I know. That's why they teach courses like this.