Finally got around to making this earing, and I'm glad I did. I think it turned out pretty well! I only hope that it will stay in place properly.
I made this with Sculpey and a paperclip, which you can see sticking out of the earing in the sub-image. Basically, what I did with the paperclip was break off any excess, then stick what I had through my fursuit's ear. Once I let the foam and fur relax back into place, and once I align the paperclip properly, the opposite tip of the earing prevents it from backing out randomly. It would take a bit of manual finagling in order to remove this prop, and that's exactly what I want.