Setting: First person is lying on the ground on his back and appears to be unconscious. Second person and third person walk up and notice the unconscious person.
Second: Oh no, he looks unconscious. We better start CPR.
Second and third kneel beside the first person. Second person starts chest pumps while third person counts.
Continue this for about 15 - 30 seconds.
Second: I'm starting to get tired. Let's switch positions.
First person sits up and prepares to do chest pumps. Third person lies down and becomes the unconscious person. Second person starts counting.