1.) The process of Bonding, but between two or more good male friends, or bros.
2.) An activity involving two or more straight males that could be perceived as homosexual if witnessed.
"Me and the guys are goin' up north for a fishing trip, gonna be some serious bronding done this weekend."
Matt: "Man, mike kept complaining about sleeping on the floor, so I finally let him sleep in my bed with me."
Brian: "That's borderline gay, dude."
Matt: "Nah dude, pure bronding, that's all that was."
Originated with Australian prison inmates who would resist transfers/court appearances by smearing themselves with their own faeces - derived from the analogy of applying 'bronzing' sun tan lotion.
"They smeared themselves with their own waste, but the protest (known in jails as bronzing up) proved futile when they were later told they were not required at court." News.com.au, September 17, 2004.