Point your feet out away from each other and squat down as though you are riding a horse. Bring your arms up and out and sway side to side.
Horse pose is a very grounding with strong legs and feet rooting into the earth. It can be easily made fluid pose by swaying back and forth.
"Pretend you're riding a horse and that you need to hoist your foot over the saddle!", "Can you dance back and forth in this pose?" "Push your hands away for an extra stretch in your arms!"