Bastinado - punição

This is probably the cruelest punishment that can be delivered. No marks, no outward signs that the recipient has been punished, but the suffering of having this administered is excruciating. What's more, the critter has to walk around all day on what feels like broken glass. Do not be fooled, it may not seem as though I am hitting him very hard, but that is for a reason. Just hard enough to cause real suffering, but any harder and he wouldn't be able to walk, and I want him to walk, I want him to remember with every step that he is owned by me.