All the tickling I've ever been involved with, or witness to, has been of the vanilla/platonic/playful variety -- generally the kind of stuff people who wouldn't frequent a board like this do -- and as such it's always 100% non-consensual, which is what appeals to me.
Because tickling is something that people generally don't like to have done to them -- the instinctive physical response is one of aversion -- and something that people do to other people because they don't like it -- because that instinctive aversion response is amusingly paired with appealing laughter.
This doesn't mean tickling someone to the point of anger, or beyond endurance, or in spite of desperate pleas or miserable screams -- it just means that the ticklish person is saying "no NO don't" between the laughter, and the tickler is perpetrating it because of that response.
Of all the people who've ever tickled me in my life, all of them did it because of an expectation that I don't like it; if I'd said that I did like it, most of them would not have tickled me.
That playful, friendly, affectionate brand of non-consensual tickling is what I tend to prefer.