Here's the rules...
When a newbie (non smoker with less than a year of smobriety) posts, they add +2 to the number...
When an Elder (non smoker with more than a year of smobreity) posts they add -1 to the number
You have to wait until someone else posts before you can post again 
When either +20 or -20 is reached then that team wins the round... A new post starting a new round with 0 then it begins again with +2 or -1 depending on which team you are on 
I copied this from a post by a friend from QSMB, lizasaidwot,
Thanks Liza!
Click the above image to see how to post.
20 We win! 
