Start standing with your feet slightly wider than hip-width apart, holding one dumbbell length-wise in both hands.
Inhale and twist upward to the right, bringing the dumbbell above your head. This is your starting position.
Exhale, and slice the weight diagonally across your body, ending twisted to the left with the dumbbell outside your left thigh. Pivot on your feet as needed.
With control, lift the weight back up to the starting position. That's one rep.