I wonder if there's actually a non harmful way of releasing the yukkuri from a balloon. If you pricked it with a pin or whatever, the loud bang would surely kill it.
I'm remembering this trick I learned in primary school where if you put a bit of tape on the balloon, then pierce that, the air flows out slowly.
Also, I wonder how long a yukkuri could last inside a balloon, different artists differ on whether yukkuri breathe. You could have a yukkuri going insane by being inside a balloon filled with laughing gas or something, or have it trapped in a novelty balloon in the shape of cute animals, the helpless yukkuri at first being overjoyed by "flying in the sky" and slowly whining and complaining of being lonely as the balloon shrinks and you throw it out.
For all the possibilities you could explore by trapping a yukkuri inside a balloon, this fart thing is pretty unique, I have to admit.
To a few fanons, they only believe that they need to breath (for example, pool #1070). As long as it where to get food to replace its expiring paste, it wouldn't notice the air unless some anon informed it.