This hardly ever works. Honestly, dipping face in ice water is a bit better I have found over the last 20 years. Valsalva is not bad also.
The coolest ER trick is probably the parent’s kiss… bead stuck up your kid’s nose? Don’t bring them to the ER, just close the contralateral nostril, and blow in the kid’s mouth!
The bead pops right out, and it’s super satisfying.
I have accumulated hundreds of these little tricks over the last 25 years!