I personally have two similar hiccup methods that seem to work well...depending on how tolerant you are for discomfort!
Holding my breath by itself doesn't seem to work very well anymore, so...
1) Hold your breath and run around in circles for 20-45 seconds without breathing again. Sure, you're gasping for air at the end, but normally when you get calmed down the dang things go away.
2) Hold your breath and tighten your abs and throat...it will force you to gag a few times, but I have this theory that the gagging releases the diaphragm to its normal state and gets rid of the hiccups that way.