The weirdest one I've tried that works is take your pinky finger and just barely, almost imperceptivly, rub your ear lobe with it. The only reason I can think of why it works is because you focus on not touching your ear too hard or too soft and just... Forget to hiccup? 🤷🏻♂️
Smoking (green or otherwise) is also supposedly a way to stop hiccups. It can, however, also cause them in the first place. I usually find the latter more true than the former, personally. 😅
Have an upvote for the advice, but that ain't working for me right now. Sometimes the mustard trick seems to work for a couple hours or so, but that's hit and miss as well.
I dunno, guess I'm gonna pack a bowl of green and see if that helps.. 🤷♂️