The real people I know use sterile, one-use acupuncture or piercing needles, which seems like the safest route… They don’t have quite the aesthetic simplicity of a pin, though, do they?
And Harold, my mother told me that, too! Whenever we got splinters, she’d make use get a sewing needle and hold it over a flame, telling us that the metal in pins was impossible to sterilize. I’ve mentioned it to a few people and they looked at me like I’m nuts.
The typical sewing needle is made of a finer grade of steel, and is sharpened more acutely than the typical pin, and therefore may be inserted with a lesser more controled force.
Perhaps it’s “needle” play because of the confusion one might encouter when speaking, if one mistakenly heard “pin” play as “pen” play, or perhaps because of the double entendre “to prod, goad, provoke, inflame, tease, torment, taunt, incite, arouse, or bedevil”…