Hi,
My teacher tell me hip motion is a natural result of weight transfering. I try do that, but I failed (my teacher and me know my hip motion is just like sway my hips not "hip motion"). After I obseving my teacher, I realized that his shoulder are slight moving ryhmtic with hip motion. on other words, his body wasn't very "solid" but his should also kept stable. And his arms can move with motion natually.
I saw many great dancer used many arms action when dancing. My teachers said it is move with body natually not on purpose.

But I can not do it as he said, I always feel I didn't know when to extend or contract my arm, should move it fwd or bwd. Finally, I got an inside that is arms actions maybe related to hip motion. Because I found that my teacher shoulder was moving sligh fwd when take LF check and starting to tranfer weight onto RF(Rumba QQS: the downbeat of first Q).So I think it was something like CBM, so LF fwd casue Rside moved sligh fwd, that made R arm to extend.(I didn't know if my ideal was right or not?)

But I try put my weight completely, but my shoulders and arms "could not" feel the power to move with the body action. That make me feel like just sway my hip.(my teacher also pointed out)

When I asked My teacher, he told me to used muscle on my back of ribcage, then you can do the hip motion, but don't move your shoulder. Is it right?
But as for how to practice it? Frankly, I don't know, my teacher don't tell me clearly.
I remebered my previous teacher, taught me that :"Use the muscle between belly and the under part of our ribcage, not use your hip". I don't know how to named it in english, but I known it is on both side of your middle torso. But this palce is seem without muscle to control .....

So maybe some nice people can tell me how to practice it, and help me to understand what is the hip motion and arm action.

Thanks in advance

1:
Hip motion is "The rotation of the hips around the spine". Do it mean hips rotate parallel to spin or vertical to spin?