What's the difference between degradation and masochism?

One is words, the other is sensation. A degradee wants language that would be unacceptable anywhere else; a masochist wants physical intensity.

They're negotiated very differently. Physical limits are reasonably easy to describe and you find the edges gradually. Words are not: one specific phrase can land as thrilling and the next can ruin somebody's month, and there is no way to guess which.

Anyone doing the verbal kind should be writing down the exact words that are in and out, in advance.