People tend to throw out the phrase "extremely specific kinks" as though that inherently implies something transgressive, but in my experience, the overwhelming majority of extremely specific kinks are so innocuous that you could see them in public and not even clock them. For every person who can only get off to having their nipples electrocuted, there are a dozen who are volcanically aroused by seeing their partner wearing one specific pair of socks.
Extremely specific kinks in fiction: I need several thousand dollars worth of equipment to act out an elaborate roleplaying scenario whose particulars are intimately linked to my childhood traumas.
90% of extremely specific kinks in reality: I feel tingly when I hear the word "passport", and for the life of me I cannot explain why.
