Judging from the last game, a Mason is just a villager with a little more information. The mason knows the other members of the "masonic brotherhood" and thus can discount them as possibilities for werewolves.

You can make your vote as a block, and also try and protect each other during the day, offering arguments as to why an accused brother would be innocent.
Beware though: such actions can make the brotherhood of masons look like the brotherhood of wolves.

Since you know eachother, you can also send PMs to eachother. DungeonMaster77 ruled that seeing as he couldn't enforce "nightly" meetings, we could PM whenever we chose. However for the most part we didn't bother. There is enough communication during the day in the banter to see where people are voting. A couple of nightly messages were passed as to who we suspected. I did so on the night before I was killed, because I was half expecting to be a target (its not like there was a lot of choice left).