[te]

Or, just try holding your breath for 30-45 seconds. I'm betting you've discovered a round-about way to achieve the same mechanism of action (raising level of CO2 in your blood). https://www.bbc.com/future/article/20140127-do-hiccup-remedi...

[ayeung]

My (somewhat weird) roundabout way is to take a deep breath in and exhale slowly while imagining myself at a time (like say 5 minutes ago) when I did not have hiccups, but it requires concentration (usually 5-10 seconds).

[grecy]

For that method, I have to clench my abs as hard as I physically can, and usually a hiccup will still force its way through.

It does work, but it's not easy and usually take 5+ attempt to stifle the one that forces through.