A work in progress, currently at the functional prototype stage.
The top image shows a water pistol. It straps to the dorsal surface of the wearer's pronated forearm and is operated by flexing the fingers against the bar beneath the device's tip.
The pistol connects by a hose to the backpack, which holds 10 litres of water and has a crank at its side to maintain pressure. The backpack also features shoulder-mounted water jets and a chimney for venting gas. Expect updates on this contraption in the future.