I grew up in the late 60s/ early 70s watching Three Stooges and Little Rascals reruns. One character was always trying to stifle another’s sneeze by placing a finger horizontally underneath their nose. Is that something people actually used to do? Does it ever work? It doesn’t for me. heck, I mostly sneeze through my mouth anyway!
Yes, it works for some people. Me, for example. Not you, obviously.
It works for me, but it really only works if you press the finger pretty firmly against your philtrum (the groove between your nose and upper lip), where it meets your nose. Just placing your finger in that spot won’t do it, you have to press.
There’s even a TV Tropes page:
Okay, but did people, once upon a time, perform this maneuver for others? Or was that just an odd Hollywood thing?
I’ve tried it on my wife before. Sometimes it worked, other times I got my finger sneezed on.
Granted, many of the times it “worked” were when she pulled back asking “What the hell are you doing?” 
You‘ll be blocking a branch of the trigeminal nerve, which will literally reroute the neurologic signal that is sent when your body is preparing to sneeze.
FWIW, I pinch my nose shut. Works around 75% of the time.
In other news, can anyone trigger a sneeze? I can, by scratching my temple, just above my eyebrow. Handy when a sneeze just wont come out - doing that gets the sneeze to, uh, finish.
I look at a bright light. If a sneeze is coming, that clinches the deal.
Does it cause you to sneeze otherwise? Or only if you already feel like sneezing. I’ve always been fascinated by this reflex, and knowing you can only halfway have it could be interesting.
When my daughter was a baby, she would start sneezing every time she was exposed to the sun.
This would have been good to know just yesterday, when I was eating a raw carrot.
In the middle of chewing, a powerful urge to sneeze came on. Not wanting to spray a million tiny pieces of mostly chewed up carrot everywhere, I closed my mouth most of the way and tried to route most of the force of the sneeze through my nose. It mostly worked, but anybody seeing it would have thought I was having a seizure.
Am I the only one who enjoys a good sneeze? I like to really cut loose, assuming it’s the right time and place. I can rattle the neighbors’ wind chimes.
mmm
Many years ago there were a couple of coworkers that I would regularly go to lunch with. As we’d walk out the door of the office building into the sun, one of the coworkers would count down “3… 2… 1…” and right on cue the other guy would start sneezing like crazy, rattling off about half a dozen in a row. It was almost like some bizarre parlor trick.
And no, I never stuck my finger under his nose to see if I could keep him from sneezing.
If we’re gonna link to an article about Photic Sneeze Reflex, how about this one from a column by some guy named Cecil Adams:
Same here. It nearly always works provided I press HARD.
One of the directors at work ended up having surgery after injuring his neck suppressing a sneeze while in church. The general advice is to not do it. The Potential Dangers of Holding in a Sneeze
It works for me sometimes. ALso…saying to yourself several times “Ice Cream” (“grapefruit” also works)
But I have to push the end of my nose up with my finger…just holding my finger under my nose does nothing.
So, I walk around the house on occasion pushing my nose up with my finger saying “Ice Cream”…its quite the visual, I’m sure.
I was always told the same thing. Do Not sneeze towards other people or things, but use a handkerchief to catch the blow-out and let rip.