Oh, before I forget... I tweaked this a bit from a couple versions online.
Harmony Flute
• Background Points: 1
• Gnosis Rating: 5
• Spirit: Peace, Calm, Water or Bird
• Appearance: A hickory flute, adorned with the feathers of songbirds.
• Effect: When activated and played (which requires a Performance roll), the flute emits an enchanting harmonious melody, reawakening ancient memories of peace. Creatures without Rage may not resist the effects of the flute. When a raging creature hears the song, the Storyteller must make a successful Rage roll to continue, or they will cease fighting. Conversely, Gwydions in a Berserk Rage may make a additional WP roll to cease fighting. (An affected creature may still defend itself if attacked.) This effect continues only as long as you continue to perform.
I also like the idea that if you really don't have performance, you could spend glamour, or try a persuasion roll to convince the songbird spirit to sing for you, and all you need to do is blow.