Is it normal to cum while being tickled?

Okay so what happened is I have a couple of friends on the bus(I am a senior) who love to tickle, and together they are ruthless. Anyways what happened was they both restrained my arms with their arms and they both proceeded to tickle my sides stomach chest pits and thighs, almost my feet, but the bus driver stopped them(thank god) for a little bit, but it was long, and hard enough for me to lose control and almost freak out, but then that familiar feeling of pleasure came rising up and I came all over myself, and they didn't even know because they kept tickling me, and when they let go all I felt was that, well that, and left with the thought of, 'Did getting tickled really cause me to cum all over myself?'

Does this mean I have a tickle fetish? I never looked at tickling as a way to pleasure myself, or anything with. The thought of it happening again is both terrifying and exciting at the same time. I never felt like this before, in my life at all even when I was younger being tickled was for fun, and it was not that much, maybe every other complete solar eclipes.

Anyways, they do a lot of tickling, once almost every week. Twice if they feel like it(Which is also a lot) if they had access to rope I wouldn't doubt them on using it.

For the longest time I never thought how tickling can do something like this. I knew the chinese used it as a form of torture to keep someone from stealing or whatever, but pleasure? Is there really a group of people that are like that?

(PS. This is the first time I came to them tickling me)