When I was growing up, I had constant allergies. In the summer, many, many things in the outdoors would set me off. In the winter, dust and mold kept me reaching for the Kleenex. I was forever sneezing and blowing my nose. This culminated during a trip to Friday Harbor in the San Juan Islands with my husband-to-be. We were at an outdoor restaurant and I was sneezing so hard I could barely eat my barbecued crab sandwich. Tears were streaming down my face, and the diners around me were starting to edge away. Finally, a kind gentlemen came over and told me what I should do about it. It sounded completely bizarre and I didn't believe him, but I also wanted to eat my lunch. So finally, I excused myself to the bathroom, tried what he suggested .... and it worked. Ever since then, it has been my secret weapon whenever allergies give me grief and I start a sneezing fit.
Though this cure can be done anywhere, it is easiest in a bathroom. Not only because it looks very strange, and bathrooms have a modicum of privacy, but because the sink is very handy. Step one, enter the bathroom and wash your hands.
Turn on the faucet and cup your hands beneath it.
Once you have a little pool of water in your cupped hands, dunk your nose in it until it is submerged. Hold it there as long as you can.
Release the water. You may repeat if you would like. Especially if another sneeze escapes.
Dry the outside of your nose with a paper towel, or whatever is handy in the bathroom. Or you could let it air dry. It may feel tender and tickly, but you will no longer be actively sneezing.
You are sneezing uncontrollably because of some irritants in your nose that for some reason aren't getting sneezed out. The water damps everything down, including the irritants. Non-airborne irritants aren't going to make you sneeze. So you can use any water anywhere. I've used bottles, hoses, drinking fountains, whatever is handy.