YSK How to stop hiccups
Why YSK: they are annoying and can become painful.
YMMV, but this process hasn't failed me yet.
You exhale and then take a very deep breath and hold it for 10 seconds. Then, without exhaling, you breathe in again, pause, and then breathe in a third time. The doctors theorize that stacking three inhalations in a row stops hiccups both by increasing CO2 levels in the blood and by immobilizing the diaphragm. https://www.health.harvard.edu/staying-healthy/stopping-hiccups