Hiccups occur when there are spasms in the diaphragm.
Here are two of several acupressure points that help stop the hiccups.

The next one also works to prevent a sneeze to come out.

If the above doesn’t work, try these methods especially the Awoga Method!
http://www.wikihow.com/Cure-Hiccups
*If the hiccups persist please seek a medical attention.