I've done it before.
I was strolling through a park when an attractive blonde girl caught my eye. She was sat alone on a bench. So I sat next to her and made conversation. We hit it off very well. She was from Poland on a connecting flight/coach back home and had some hours to kill. We talked for a while.
I then noticed her feet in some white backless slippers. I asked why her feet were so dirty and she said they weren't and i said they were (which they were) and she said she was strolling barefoot along a beach that morning in Turkey. I gently touched them to indicate dirt but nothing happened.
We continued talking and then i just asked "are your feet ticklish" and then i grabbed a foot and tickled it. She burst into laughter immediately and said stop. I thought about stopping but it was such a healf-hearted "stop" that i continued and she loved it.
I grabbed the other foot and did the same and then i said are you ticklish here and tickled her waist.
She clearly bloody loved it.
I then said -"go and lay down" and she said no at first and then ok and did and I layed her on tummy, took off shoes and went into town tickling her feet whilst she laughed and loved it.
She was a 21 yr old university student from Poland - studying politics i think.
I then said i would show here around london and we got up, but she tickled me back - all she wanted was tickling.
We walked from one part of the park to another and sat down under a tree and we talked and i tickled. I must have tickled her for over an hour, perhaps closer to 2 hours in total.
She tickled me back and seemed to love it a lot, until we parted ways.
I wouldn't even dream of doing something like this now, but a couple of years ago I did and it worked out very well.
I say don't do it. But I did at least talk to this girl for a while and she really, liked being tickled.