You deploy then experience the risers and/or lines are twisted above your head. Sometimes you are turning as well, and on medium performance canopies, you may be spinning violently, likely with the slider up high on the lines.
If the canopy has opened normally with no twists, but simply turns on its own, be sure both brakes are released. One toggle may have come unstowed on opening.
If the canopy is centered above your head, not spinning or diving, pull apart on the risers and kick, just like if you were in a swing in the park. You can also squeeze the risers together and untwist your body underneath, as if you were wringing something out. Keep looking at your altitude to gauge the amount of time you have to try and fix this, with your decision altitude in mind.
If the canopy is spinning, diving, and you are not oriented underneath it, pull the cutaway handle followed immediately by pulling the reserve ripcord by at least 2,500 feet.
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