Whenever I see the phrase "sadistic tickling," I am unsure of what the person is referring to, not because I don't know what the word means, but because sometimes it's used as a proxy for things like extreme or unbearable. And even when they technically do mean sadistic, I still think of two distinct forms of that: One being deriving pleasure from the lee's reactions and difficulty tolerating the tickling, but the lee still at some level being okay with the activity; and the other being deriving pleasure from not only the aforementioned elements, but also from the knowing and experience of the lee not being okay with the activity.
So if you're just referring to something that's very extreme and goes on for a while, I'd say that happens between my wife and I often, and occasionally with a play partner
If you're referring to the first type of sadistic tickling I mentioned, I'd say that happens on occasion to my wife, but most often me. I have an ongoing request for receiving this type of tickling. It does a lot for me, to include stress relief, mental and emotional recalibration, and it's just fun. My wife and other play partners have done this to me many times. I don't use safe words during this sort of activity. My wife and the other play partners so far have been ticklephiles that enjoy my reactions at this level, so it works out. In addition, I've seen a few over the years "in the wild." As I recall more I'll write about them, but I did write about one
here.
The last one is essentially abuse. I think it can be seen differently and appreciated if kept in the realm of fantasy, but in reality it's not okay and I don't want to think about it, let alone share any observations of it.
