As a prep tech (at Expressway Cinema Rentals) one of the most commonly asked questions I get is "Do you have a paperclip so I can pair the teradeks?" And we used to have paperclips with tape on them, but they kept going missing. So when we got a 3d printer, one of the first things on my list was a teradek pairing tool. After many iterations of different forms (see photo), this seems to be the one.
It is a twist pen that prints in two parts. Once it's off the printer, unbend a metal paperclip and heat it up (a lighter works best) and stick it in the hole of the inside part. Put the two pieces together and trim the paper clip with a pair of wire cutters. It's retractable, and the diameter of a sharpie, so it will hopefully be less easy to lose than a paperclip!