Caveat: I am not a natural turner. There are beautiful dancers who can simply move their heads and they spin like tops. That is not me. But I am consistent. I know what I have to do in order to perform a double pirouette en dehors or en dedans - and if I am not performing it properly, I know how to fix it for my body.
This is my goal for you. Consistency. Knowledge, as the saying goes, is power, and the more knowledge you have of proper pirouette techniques, the better able you will be to control your turns.
Let's talk plie in the en dehors pirouette. First of all, we will assume that you are:
1 - pulled up in your abdominals
2 - engaging your upper back muscles
3 - elongating your neck and arms
Now, let's try the pirouette. From a 5th position, left foot front, either tendu or chassee to a 4th position tendu with no weight on that right foot. All of your weight is on the left foot.
Hold the tendu for 4 counts, stretching the arms and back and toes even further, then do a quick plie on the "and" count, reach the right arm even longer, pull the arms to first position, bring the right leg up to retire, and turn on 5. End the turn nicely with a soft fondu to a 4th position.
There are several advantages to trying the pirouette with this timing. For one thing, it avoids "sitting" in your 4th, which usually redistributes the weight incorrectly to the back foot or between both feet. For another, it takes advantage of the snap of the "and" count. And most important of all, it eliminates the anxiety many dancers feel when they turn. So many of us think, "Oh no, now I have to turn!" Then we sit in our plie, wind up our arms, and hope for the best. By using the power of the "and" count and the quick plie, you can remove anxiety from the pirouette equation.
Try it next time you're in the studio. And keep in mind that this preparation is not necessarily appropriate for all combinations but it can get you re-thinking your plie so you can use it more efficiently.