gone

For what I have read in a wiki: "A cheesy way to farm Vertebra Shackles is to get a friend to summon you via the Red Sign Soapstone and allow you to kill them repeatedly while you are a Mound-Maker. They do not need to have their Ember to summon you, and if they stay near a bonfire they will have no risk of losing any souls they may have. They don't even have to be near your level. Set a password so only they can summon you, and farm away. Profit."

Didn't test it already.