The reason you're so obsessed with it is because you don't allow yourself to indulge since the feelings are overwhelming and they thus make you ashamed because you feel different from others, but that way of thinking / acting is a cycle that just kinda keeps going until you try something new.
I realize I'm a girl and maybe my way of going about it won't apply, but I pretty much figured that in the grand scheme of things, tickling is not a big deal. I mean, I don't like being burned or electrocuted or hung upside down from hooks in my knees or being pissed on or fucking animals, so it's like really... how embarrassed should you be? If it makes you happy, why hold yourself back from getting what you want?
I tend to bring up the subject after about 2 or 3 dates, give or take, if I feel like things are going well so far. I avoid the word 'fetish' since that translates into 'mental issue' or something in the vanilla's brain, and I make it seem like it's not a big deal, just something fun, that I'm into. I've never gotten a bad reaction (although I'm a girl who likes to be tickled so I know that's a bit easier to ask of someone than "hey can i tie you down and torture you") however, if I was in that situation again and there was a negative reaction, at least I know I brought it up early enough to move on to someone else without all kinds of emotions being involved.
The more you talk about it, go to gatherings, indulge yourself, the less ashamed / obsessed you will feel.
True story.