How Do Gas Nozzles work? It’s funny that you ask, because we have The answer right here. When you squeeze the handle, the opening is gaped and can flow out down through the Venturi. This is so that people can’t come and get gas whenever they don’t pay for it. You can squeeze it, but until you pay for it them. The nozzle can be held open, but the person who grabs it won’t be covered in gas because of a new invention that works as a sensor port so when the amount you pay for is done, the pump will automatically turn off.