For those who said that they were tickled and not asked, I must confess, I'm guilty of non-con myself, but, it was when I was a vanilla, and long before I realized tickling was a turn on.
Two experiences I recall clearly, with girls where loving feelings existed on both sides, but we couldnt get together, due to circumstances.
Freshman year in college: I start hanging out with this girl Lora. We really liked each other, but she was going through a confusing time, where she thought frat guys were it. When I asked her to be serious, she told me she really cared about me, but wanted to play the field. Fine. Sexual tension still existed between us.
One night, we're in her room, and she's lying on her bed, face down. She says something like "Mitch, I'm sore, give me a massage". Naturally, I did.
I start massaging her. Back,. sides, legs, etc. When I get to her feet, she was barefoot, and I started rubbing them. Finally, I pinned down her legs and feet, and began tickling her soles. She went nuts, and said something like "If you dont stop tickling me, I'm going to want you to stop massaging me". Due to the fact that I was more into touching Lora's body, then tickling, back then, I stopped, as the big thing to me was to get to touch Lora, and not to tickle her. I didnt ask Lora if I could tickle her, it just happened.
Several years later, when I was a senior in college, I had another friend, Stacy. Before she met me, she started going out with a good friend of mine, but then realized she really loved me. It was an extremely awkward situation. The incidents where I tickled Stacy aren't as clear in my mind as the one where I tickled Lora. All I remember is tickling Stacy's ribs a couple of times, without asking. She knew I had a foot fetish, because I told her. Stacy said something like "I'd probably let you tickle my feet if you wanted to, but I might go crazy if you did, because I'm really ticklish". The opportunity to tickle Stacy's feet didn't happen, but, if it had, I doubt I would have asked her, I just would have done it.
I'm beginning to think the whole non con thing is because the people who are tickling are consciously aware they have a fetish, so there is a stigma is doing something sexually related to another person, without consent.
It's the same when it comes to foot fetishism: I'm sure plenty of guys without foot fetishes might kiss their gfs feet and suck on their toes, during sex, and it would be no biggie. As a guy with a foot fetish, though, I'd want to explain my fetish to any girl I was with, so that if she saw me getting excited while doing it, she wouldnt think I was creepy for wanting to touch her feet, without her knowing why.
I guess it boils down to alterior motives. Vanillas dont think "Oh, I'm going to tickle this girl to get turned on". They think: I'm doing it to be funny, or to play around with them." In that concept, non con is no biggie. However, a tickle fetishist guy like myself is viewed in a different light. I'm sure if I dated someone, and tickled her, and then said something like "When I tickle you, it turns me on. I get an erection, or I fantasize about myself or someone else tickling you". That would creep her out, especially if she wasnt into this.
Unfortunately, there is a huge double standard between fetishist acceptable behavior, and non fetishist acceptable behavior. It will probably always be that way, because, not many people outside our world of interest understand why we like tickling or other fetishes, and why they turn us on so much.
Mitch