Play misty for me, one time... sounds like a cool idea. what if there was on the back of the chair, an arm that extended up? The arm would collapse and tuck away when the chair folds. The top of the arm could have nozzles spraying for you.

you could have a small plastic water tank that had a little hand pump to pressurize the tank and spray you if no water hose. Like the little portable misting bottles only on the line of a garden sprayer.