Why does Pinkie Pie have a strong relationship with Rainbow Dash? - Sugarcube Corner - MLP Forums

I always wondered why Pinkie Pie and Rainbow Dash have such a strong friendship?

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Action Figure Insider » DISCOVERY FAMILY CHANNEL INTRODUCES THE NEXT MAGICAL CHAPTER IN THE MY LITTLE PONY UNIVERSE WITH BRAND-NEW SERIES MY LITTLE PONY: PONY LIFE #MLP

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Why does Pinkie Pie have a strong relationship with Rainbow Dash? - Sugarcube Corner - MLP Forums

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Why does Pinkie Pie have a strong relationship with Rainbow Dash? - Sugarcube Corner - MLP Forums