It may be that hiccups are caused by low levels of CO₂, so raising this will inhibit the hiccups, or some think it's a way of distracting ... obvious many of these ‘cures’ don’t have ...
The quickest way to stop hiccups is to stimulate the vagus nerve. Most hiccup cures, like pressing your eyeballs, pulling on your tongue, sucking on a lemon, plugging your ears, the Valsalva ...
which forces muscles to contract in a way that stops hiccups. As for why slowly eating peanut butter sometimes helps people cure their hiccups, internist Tyler Cymet told The Guardian in 2014 ...