When do you pick Braum?
Title.
Title.

if their team comp looks like this or some shit, it would be a great idea to braum
Nah when ever you want I just played against Cinderhulk Braum it could 1v1 me as Graves. I was so mad that item is broken.
Luckily still won the game because Kalista just bought bad items lates game.
This might help, since it goes pretty in-depth.
Whenever you want an easy botlane with Lucian or Graves.
They picked 
Braum is freelo in that situation
Dat ult
Dem balls.
Dat cocoon,
Dat afk
Dat EVERYTHING
Just click E in teamfights.
http://i0.kym-cdn.com/entries/icons/original/000/006/077/so_good.png
when I need to carry puny adc
I only pick Braum when my ADC wants me to pick Braum. He's not really my favorite champ, and I prefer Leona as a CC tank. Braum has his shield, which is awesome against some champs, but I generally don't rely on gimmeks