During holiday seasons like Christmas, Daiso ($2 shop) will have cute Santa or Reindeer shaped hair band for kids. The hair band might be too big for the lens but here's something I did before to not waste that "prop" I bought for an event. I cut 2 holes at the ends of the hairband, and took out the plastic piece and ran a string/rope through the vacated zone. You can then use the string to tighten around our lens like a drawstring bag. Hope this helps.
Looking forward to your review!
looking forwards to photos of the product! i have a feeling it is gonna look like those macro ring flashes
might as well put a troll face on the lens