Similar to "no homo". If brohomo is called, the prior/proceeding action/statement cannot be looked down upon or called 'gay', because the two persons in question are bros.
Bro A: "Dude, I saw you fuck that chick last night."
Bro B: "...you watched me?"
Bro A: Brohomo man.
Bro B: "...you watched me?"
Bro A: Brohomo man.
by Johnny Knockers September 28, 2010