From The Black Books of Elverum, Mary S. Rustad edition:
To calm anger
Take the heart from a swallow and spear it on a stick. Then take the tongue of the swallow and place it under your tongue. Then display the swallow's heart. When someone is angry at you, display the swallow's heart, then place the bird's tongue under your tongue and speak to him. His anger will stop.
The grimoire The Black Books of Elverum lists this spell.
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