I thought of an image to guide students (and myself) in how to raise
the hands effectively. Because they tend to follow the strings or raise
toward their body, I tell them to raise up, drawing up from the earth.
This produces a fully felt, meaningful gesture, that automatically
draws the sound up with it, with full resonance, and it has meaning.
This way their movement is in relation to the floor, which produces the
right angle of movement, without any confusion about direction. And if
they shake their hands as they do it, they can produce a nice “vibrato”
effect, too. Try it!