It's a lot like the ancient
Christian orantes posture: kneeling or standing, with both arms out to the sides, palms upward. Often the face is turned upward too. God's blessings are raining down and I don't want to miss anything. I remember standing just like that the first time I experienced summer rain in Phoenix.
Whether you're begging or praying -- and the two are a lot alike -- you are waiting, hoping, open, and willing to accept what is given.