A buddy whom you trust with the entirety your life to survive in the outback (steakhouse) of the wild wild Australia. I mean, it's continent and a country!
(Adj.) To have earbuds placed in both ears at moderate to high volume in a workplace or social setting, in a bid to deliberately tune out others around you.
Earbuds may also be worn but not actually turned on, as a visual repellent to any social interaction.