I went to a presentation about using FedEx in our purchasing system. They handed out containers of cute little paper clips, shaped like airplanes. How clever! How darling! And how phallic they look when they're actually being used!
Somewhere, in some promotional materials design firm, there's a couple of queens chuckling to each other, "Hey, I bet we can get FedEx to give away clip-on penises..."
I've never heard of a CLIP-on.