Placebro

A Bro that is your backup Bro when you're Bestest Bro is unavailable

Jack: "Hey Chet! Do you want to Bro out tonight?"
Chet: "Ah sorry man, I've got plans."
Jack: "Ah, that's alright. I'll call up Alex. He's my placebro."

Brogy

The exciting yet excluding phenomenon that occurs when only the bestest of bro's reunite together.

Kirk: "Joe! Man it's been like 2 days! "
*insert massive man hug*
Joe: "I've missed you man! We should call up James and have a massive brogy!"