Perhaps this fits into the “lots of things will work if you’re motivated” category. When I was a kid, that was my theory about hiccup cures. There were so many different hiccup cures (holding your breath, drinking a glass of water slowly, getting startled, . . .) and they all seemed to work, so I decided that just about anything would work to cure the hiccups, if you wanted it to work and you had a plausible enough theory attached to it.
This is not to disparage Matt’s plan. It seems to be working for him, which is what’s important!
I understand that studies have found that the common cold is particularly susceptible to the placebo effect. Me, I believe in orange juice, and it seems to work; if it doesn't work for people who don't believe in it, that's their problem.
Stopping the hiccups for me has always been about relaxing the responsible muscles. Once I figured that out, the hiccups never last more than a few seconds. The same type of control seems to help with singing, too – I wonder if singers tend to have less trouble with the hiccups?