In fact, I have one thick ring on my left thumb (my mother's wedding ring) and four thin rings on my right. I often get questions about how I can bend my thumbs (um... just as easily as any other ring) and if I ever take them off (no). Recently I was asked when I started wearing them and I didn't even have to think about it for a second. I've had some sort of ring on either or both thumbs since 1985. I was inspired.
That was the year that Mad Max Beyond Thunderdome came out. Tina Turner looked amazing to me as an impressionable 18-year-old, and her character Aunty Entity was so freaking badass. She wore chain mail, had a wild wig, and she had a thumb ring. I copied the only thing I could. And that's the story.