Every stroke of the knife, every pound of flesh, every time I used healing potions to prolong life as long as it would go. I could feel their terror growing, swallowing every other emotion they could feel. I could feel their pain too and it gave me sick satisfaction that a cruciatus curse could never give me. The torture curse for all the use it gets is actually quite useless at providing pain at the highest level. Solely because if every nerve in your body is lit up with pain at the same time the brain will just short out and be unable to process the sheer volume of information. No, this method was so much better, I'm certain they can feel the sting of every cut, the dull throb of pain with every chunk missing. They can't pass out to escape and they have nothing to concentrate on except terror and pain.