I wanted to elaborate further from my original post: Everyone will react differently; some people may think it's bizarre and sick, some people may think it's cute, some people may think it's really sexy and some people may be unphased. A tip I discovered is "IT'S ONLY AS AWKWARD AS YOU MAKE IT."
The first time I ever told someone, I was very nervous and building it up like this huge dark secret and it came out like "I... I am really... turned on by feet.... and tickling them..." and I came off like a total freak.
In later encounters, when hitting on women I would just confidently say shit like "you are literally perfect from head to toe -- even your feet are sexy." And they'd be like "...my feet...?" And I'd confidently say "yeah, I think your feet are sexy and I don't care if that's weird." And I come off so cool that THEY feel stupid for making a big deal about it. When it comes to the tickling thing, when the relationship has evolved into sexual territory I usually say "hey, what are you into? And don't be shy or think I'm going to think you're weird, I like weird stuff myself." And that usually leads them to ask what I like and I preface it with bondage and enjoying seeing my partner squirm and then I just confidently and non awkwardly assert that I really like tickling. Most of the time, as long as YOU aren't coming off weird or nervous when you have these discussions, people seem fine. They just chalk it up to one of the many kinks that exist.