What I realize is (talking is a girl) - most girls/women would be open to getting tickled if the guy does it the right way without putting them into too much of a torment. If you managed to 'introduce' tickling to them (especially if they were/are very ticklish), you have done it right for sure...
I think this is exactly how people who are genuinely ticklish tend to feel - not being able to handle for more than 1-2 seconds. If someone can actually take it for hours as some people here want to tickle, I donno if they can be really that much ticklish.
But hey, hope you have fun with your...
My ex (who got me into tickling) used to lick on those spots because it would tickle me.
Of course fingers make me feel more ticklish (except in ears), but the tongue tickles feel a little different and make me giggle and squirm in their own way.