comes from the slang word "Bro", which is used often by cool males when speaking to their friends that are sometimes not related. "Broly" denotes a friend who is into hardcore iron pumping weight lifting, not penis pumping.
examples of brolyz:
and much more
examples of non brolyz, or ex brolyz:
christofurrlayer - MIA broly
HOLLA BROLYZ, I just deadlifted 600lbs and I'm not showing you a video!!!!111