Depends if you mean punishment as in penalty for disobedience, or pain for its own sweet sake. What people experience as punishment can be quite different from what they can take for their Owners' pleasure.
My ex-slave could take whips and canes till I had to stop for fear of doing her permanent damage, and still be up for more: but if I wanted to show her she had done wrong and Master was not pleased, I only had to put her over my knee and spank her. There was something about the childishness of it that made her cry and promise to do better.
I guess the worst thing I ever did to her was to put clamps on her nipples, strap her breasts down tight with tape and leave them for several hours (longer than I'd intended) while she went about her work. When I released them they were black and I was afraid that I'd have some very difficult explaining to do at the hospital; but they came back to normal colour with a lot of massageand the only lasting effect was that they were delightfully sensitive for a day or so.