Bright lights, especially flashing ones, stimulate the same nerve cluster that the urge to sneeze comes from and can help trigger a sneeze that is loading. Some people are more susceptible to that stimulus than others.
Years ago me and my sister walked through our newly built town centre together. They had installed bright white stone on the ground and both of us couldn't stop sneezing (sunny day, stone reflects sun back up). It's not as shiny now it's not new but I hate walking through that area to this day.
My usual strategy to force a sneeze over the edge is to look up with my eyes(not at the neck, more effective) and put a flashlight on strobe and it is highly effective.
Another funny human quirk is the clinically proven most effective method to cure hiccups. Especially great if your partner has them and you are willing to help. It doesn't matter how the stimulation happens either, but they were more appropriate with their testing methodology than a couple needs to be.
I wiggle my fingers in front of my nose in a sort of “multilegged gallop” motion, as if ky hand were trying to scramble up the bridge of my nose and slipping. But with no touch.
There are a couple other ones, like cilantro tastes like soap (took me some time to figure that one out) and apparently one that makes pee stink when you eat asparagus, and you need another to actually smell the pee stink (I don't know if it's true, I just got em all and collected info in the internet).
Biting into a piece of dark chocolate for the first time will cause me to quickly sneeze similar to how people do when the step out into the sun or inhale black pepper.