The capacity to stay calm and grounded when a child has flipped their lid is largely linked to whether or not you had a grownup in your childhood who did it for you.
If instead you had grown ups that flipped their lids, or ignored you, or we're emotionally shut down in their responses, you probably face a form of panic that triggers you to a less competent place as a parent.
Though I know I am hitting the therapist stereotype on the head by mentioning a hurting inner child, it's worth the risk for me if it helps even one parent give their child more calm and compassionate support.
Emotions are not in and of themselves a threat of any kind. But being a small child in the throes of them without any proper control or power and no one to help you feel safe can feel entirely threatening. And if you then enter parenthood with that unresolved trauma, you may even feel victimized when your kids lose their marbles in your presence.
But your kids aren't being bad, or hurting you. They are hurting, and they need your comfort and help.
So I'm taking a play out of my EMDR (and evidence based trauma treatment I use with clients) play book and tweaking it a bit.
When your kid loses it and you can feel yourself starting to also:
1) Imagine the safest place that you can park your inner child so they don't interrupt your parenting
2) Give them all they need to be comfortable and nurtured
3) Tell them you'll attend to their needs after your kids get what they need
4) Return to being the parent and offering your kids the kind of dedicated calm and support no one was able to give you
Hope this helps even a little bit in your journey to be a fully available well regulated support to your children in their tenderest most upset moments.