Stand with feet hip-width apart and hold a weight in each hand straight out at shoulder height, palms facing each other. Bend elbows 90 degrees and press dumbbells together (keeping elbows about 6 inches apart). Maintaining bent-arm position throughout, rotate arms and torso to the right to start.
From there, draw a backwards Z with the dumbbells, rotating left (so weights are over left shoulder).
Then move diagonally downward toward the right (bringing weights by outside of right hip).
Then rotate toward the left (to bring weights by outside of left hip). Return to starting position. That's 1 rep. Do 20 reps, continuing in a fluid motion.
Scale up: Perform on knees. When arms are on upward diagonals, lift seat all the way off heels. When arms twist down to lower diagonals, sit back on heels.