Yep, my hand. Happened to break that wrist. And no, you can’t feel it at with just that hand. Sometimes I do fidget with it through my skin using my other hand though. Mostly just cause I’m a geek and thought it would be cool to have it for building access. Mine is an RFID/NFC combo, which is why it’s bigger than the one in the article.

And if you find the thought unpleasant in general… don’t look up the needle that’s used.