This question was originally going to be saved for Purim Torah in Jest, but after thinking about it, I feel this can have practical ramifications.
How does one hold an Esrog before making the Bracha 'Al Netilas Lulav' while the person is upside down, like on monkey bars? The core of this question is, does the Mitzvah get fulfilled based on the orientation of the Esrog relative to the person, relative to the Arbah Minim, or relative to the ground?