is the boomerang’s phenomenon of falling sideways.
To understand the relation between the axes of precession motion, adjust
the thumb, index finger, and middle finger of your right hand so that they are
orthogonal to each other. As such, if the rotation axis of the top is the middle
finger, the torque axis from the difference in lift force is the index finger, and
the thumb signifies the precession axis. This is shown in Figure 10, including
the direction of rotation. Thus, we understand that in the left-turning caused
by the difference in lift force between top and bottom, and in the sideways fall
caused by the difference in lift force between front and back, the precession axis
is maintained by this right-hand rule.