Guide Forum and discussion thread go into more detail.
You only need 110 QCK to use this, meaning low level dragons can help train themselves. This runs Discipline for the extra breath, Regenerate for general grinding, and Contuse so extra turns can be used to help your fighters skip a turn of Scratch.
Put the Clobber at the end of your team.
For starting on bosses, have a fighter Haste the Clobber once. The Clobber should Meditate, Meditate, Clobber the boss.
Scratch with your fighters.
Clobber and Meditate between boss turns. Fighters Scratch and build up breath. Repeat.
Have two fighters Scratch and Elim two enemies. Clobber will stun the third.
The Clobber has an extra turn to stun 4-pack mobs. You can use that extra turn to heal off unlucky dodges, build breath back up, or whatever else.
If you have extra breath or turns, use the Clobber to Contuse the remaining enemy twice. Two Contuses from the Clobber is equivalent to a Scratch from a 133, allowing the next dragon in the turn order to Eliminate the enemy immediately.