F vs T!
My hypothesis is that feelers are the tickley ones, especially the Fi ones!
However, I'm so badly ticklish (only my feet and ears) that I cannot get pedicures, for I nearly knocked a little old lady's teeth out once, and successfully managed to splash her in the face with my feet-infused hot tub water. It was like trying to clip Cujo's nails while he was tied down onto the chair.
And I was "tickle tortured" as punishment as a kid - one time I had enough and basically smacked my father right in the face.
So! Therein lies the definition...
VERY = "tickling may very well evoke laughter, tears and/or violence from me"
NOT = "you can pumice me raw, baby!"
SORTA = everything in between