When someone's voice cracks. Once this happens, you yell "Playoffs!" in a high falsetto tone. Then you can comment about how puberty hit them like a ton of bricks. If it's really bad you can honk at them like a goose.
Normal Playoff Scenario:
Guy Who Playoffs: "Hey, what's up du(voice cracks)de?"
Extreme Playoff Scenario:
Guy Who Playoffs: "So did you che(voice cracks)ck out the ga(voice cracks)me last ni(voice cracks super hard)ght?"
You: "HONK!! PLAYOFFS!"