#1 way to STOP A TANTRUM instantly is to VALIDATE the child - their feelings, thoughts and/or desires.
Validation immediately creates 'empathy' & decreases the need to be on the 'defense'. It also puts the child more at ease knowing their Parent/caregiver is helping them through the distress rather than fighting against them or exasperating the upset. This doesn't necessarily mean they get what they want or that the adult gives in - but it does ensure that they child is HEARD. Feeling like you are not being heard, is usually the main cause for the resistance and tantrum to escalate.
Need help with this?