I like to look up discussion of tickling in kink communities and vanillas and a lot of the things being said online don't match up at all with my experience in real life.
The biggest difference is probably how negative the perception of tickling is among normal people. When a tickling question gets asked online, most people answer with "tickle me and I'll break you hands" or something similar to that. Fetishists think that others see it as creepy and are scared to tell the people they're dating. There's definitely some people like that, but I've never had a girl respond completely negatively when I told her about my kink or started tickling her. I think as long as you don't come off like you want to tie them up and tickle them until they pass out, most women are going to be at least ok with getting tickled and you can get them to enjoy it over time.
Next, I want to talk about ticklishness. If you ask what the most ticklish spot is on most people on tickling boards by far the most common answer is going to be feet since the community is mostly guys and most of them have foot fetishes. Most vanilla girls will answer with sides since that seems to be the most common place for people to tickle each other and they probably haven't been tickled anywhere else in years, or they're trying to take attention away from their worse spots. In my personal experience, not saying this is an absolute fact, armpits have been the most ticklish on every girl I've been with. Feet have always been the second most ticklish, but most could at least somewhat handle it even the first time I tickled them. When I tickled their armpits they immediately clamped their arms down and started begging. Sides and thighs are probably tied for third most ticklish, and thighs were where most liked being tickled the best. I see a lot tickle fetishists complaining about their girlfriends or wives not being ticklish at all, and I find that really odd. I don't think I've ever seen someone who wasn't ticklish at all, not that I've checked everyone, but there are people who are very good at controlling their reactions (I'm one of them). Almost everyone that knows me thinks I'm not ticklish at all, but I definitely feel the sensation when someone tickles me. I can hold back my reaction for a really long time if I want to, but I loosen up around girlfriends when they want some payback. Mood plays a big role in ticklishness and if a girl really doesn't want you to tickle her she's not going to laugh.