Stand with the legs comfortably apart, and the feet parallel to each other.
Bend both knees and hips.
Bend forward from the hip joints, keeping the back and  neck straight.
The knees are slightly bent throughout the movement.  Toes touch the floor.
When you have bent forward as much as you comfortably can, imagine reaching with your arms to get more water.  At the same time, your tailbone moves in the opposite direction of the arms.  You feel your back and sides stretching.
Start coming back up buy lowering your tailbone.  The arms stay in front and the elbows sink down.
Drink the water and feel it go into your mouth and throat, to your chest and stomach.
Lower your arms to start the next cycle.