Not sure. A few minutes every day, maybe, and I don’t know how long it would take. Obviously it won’t go all at once–even standard piercings take weeks or months to close entirely.
Of course, there’s also the surgical fix, but for such a small hole it would be just a stitch or two, no extra flesh removed.
You must admit though, they make it easier to bring in the dry cleaning.
No, you wouldn’t want to stuff a pigeon in there. Unless, well, maybe a dead one.
I meant first that some cultures have been doing it for a long time, and was implying that it’s not a “new” thing as such. Also, while some afficionados refer to “the new primitivism,” I believe anthropologists have shied away from the word “primitive” in favor of “traditional,” because it’s less prejudicial or stigmatizing. I guess if it’s fallen out of favor among the younger generations of these cultures that would qualify as generational, but my sense (or bias) is that there is some continuity to the current generation.
I also meant that I’m a generation removed from the individuals the OP has seen, and probably of most people with stretched piercings.