Tight Achilles in ballet? How can I help loosen them up?

Hi!

So today in ballet my instructor pointed out that I had very tight Achilles tendons, and that I should work on loosening them up as I have a nice arch. I have heard the stretch of hanging your heels off a step, and I already practice this, but I was wondering if anyone else knew any other stretches I could do to help?

Thanks so much if you answer, I really appreciate it!

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