Brolygamy is the art of a bro being a part of a group of 3 or more bros, usually found at the gym, mall, or PARTIES.
Bro 1: Hey dude, wanna go shopping...
Bro 2: Dude, we're not women
Bro 1: ...at the OAKLEY STORE?
Bro 3: AW HELL YEAH
Bro 4: But first we gotta hit the gym
Bro 1: I like the way you think.
Brolygamy at its finest.