Instructions
Touch the Nintendo DS stylus to the red slider on the screen. Move the slider back and forth quickly to pump up the water gun.
Tap the "Fire" button in the bottom right corner of the screen to shoot water. The gun needs a refill when the water stops.
Find a water source, like a sink, pool or even a toilet. Stand next to the water source with the water gun equipped.
Tap the "Refill" icon, resembling a water drop, located in the bottom left corner of the screen. The water gun is completely refilled.