All three times they have done laproscopic stomach surgery on me, they blew my inner cavity up with a butload of air. It would migrate towards my traps and give me cramping for a bit. I found rolling around fast in a wheelchair high on morphine would work it out because your body would absorb it, lol.
And I’ve seen then do the line of air thing to me as well. Didn’t notice anything.
I had a butt scope a while ago and that did it some too, me and a few other old farts (I'm guessing) laughing ourselves to near tears in the wake up ward, nurses at their station unfazed.