SOS
Breathe first. Then speak.
Say it in the voice of:
What to say right now · Emotion Coaching
"You REALLY wanted to stay at the park! Leaving is the worst. I'm going to carry you to the car while you cry, I've got you."
Your body first
Ignore every other adult around you. Their opinion does not matter—only your connection with your child matters in the next 60 seconds.
Afterwards
In the car once buckled: offer a sip of water and sit quietly for 60 seconds before talking. Then one sentence: 'That was hard. We did it.'
Avoid
Don't bribe with candy mid-scream (it rewards the escalation), and don't threaten to leave them ('I'm leaving without you!'); for a young child that threat is genuinely frightening.
If you're afraid you might hurt yourself or your child, put your child somewhere safe and call or text 988 (US). Outside the US, call your local emergency number.