Stand in the shallow-end with straight back. Hold the noodle with both your hands behind your body with a normal grip (about shoulder width apart).
Holding the noodle behind your back and push it down as deep as you can. Then bend your arms again and reach them up. Focus on working against the resistance created by pushing the noodle down.
Push down once with inhale and once with exhale.
Feel your triceps each time you push your arms down.