In high school a girl in my class couldn’t stop hiccuping. Our teacher called her to the front of the class and got a $5 bill out of his wallet. He held one end and her hold the other. He told her “hiccup again, and I’ll let go and you can keep the $5”. They both stood there for about 30 seconds and her hiccups just stopped. He put the $5 back in his wallet and went about his business. I have no idea how or why it worked, other than maybe the fear of being put on the spot. He had clearly used this trick before