Hi Guy,
I don't know how to do neti, I made this up when I had severely stuffed sinuses many years ago and got desperate to get it out. I stand in the bathtub, leaning the head back, keeping mouth open, holding the breath, and press the nozzle from the hose on one nostril so the water comes out again from both the mouth and the other nostril. The nozzle does not get inside the nostril but is bigger, so it's just pressed on the outside of the nostril, but keeping the opening fairly sealed. I shift to the other nostril once or twice until I have to breathe again, and then lean forward and blow the nose and let everything come out. Then I do it again until the water runs out in the jar, which holds about 1.5 quarts and is kept on a shelf about 1 foot above the head. To get the water running in the beginning, you have to suck on the nozzle, and you keep the thumb on the nozzle between the nose rinsings to prevent the jar from emptying.