Mine was a few years back now. I had been talking to this girl on Myspace and through the TMF and I finally worked up the courage to meet her. I was just out of college and this was the first girl I ever met who was really into tickling. I had a long, two hour drive anticipating what was going to happen.
I finally made it to her house and met her. We hugged and talked a little, but it was kind of awkward. She was barefoot, wearing a really short skirt and a sleeveless top. I just watched her as she showed me around the house. Eventually we ended up on the couch and she showed me the tattoo she had on the top of her foot. I took a close look and then quickly ran my fingers over the top of her foot. She giggled and said "Oh here." and placed both of her barefeet in my lap. Something about this cute girl just dropping her admittedly very ticklish feet in my lap was so incredibly sexy to me. I tickled her feet for awhile, getting faster and more aggressive as her laughter built up until she finally yelled out "Oh that's IT!" and jumped on me, grabbing my sides and stomach and tickling with her long nails. We broke into an all out tickle fight until I discovered her underarms, and she pretty much lost all ability to fight. We spent the rest of the afternoon and evening tickling the crap out of each other. Hands down the best tickling time I ever had.