Here's my method for dealing with pesky hiccups: First, I slowly inhale until my lungs are inflated to the max, holding it all in for as long as possible. Then, I slowly exhale until my lungs are deflated to the max, keeping all the air out for as long as I can stand it. Doing that procedure just once almost always solves the problem. If not, then I just repeat steps one and two above again. I don't recall ever having to do that procedure a third time. Try doing that and see how it works out for you.