It's like this: copper is merged with polyamide and the result is a type of oil that's then turned into a wire. Machines take these wires and weave them inside the undie fabric so that the processed metal stays in contact with the user's skin. This, as you can imagine, provides the user with day-long germ-killing delicates.
So it will no longer be necessary to change your underpants every week. Hooray!
http://guanabee.com/2011/08/chilean-company-creates-fungi-resistant-undies-out-copper/ -via Gizmodo | Photo (unrelated) by Flickr user Michelle loves Severus used under Creative Commons license