There’s a difference between enhancing an experience and being essential to it.
Ambiguity isn’t always the best of things—just as one wouldn’t go into a restaurant and say “some food please”, specificity is pretty useful when it comes to someone communicating what they want. When it comes to sex, lots of terms are thrown around almost interchangeably, and while their meanings overlap in some way, there are key differences.
The easiest one to define—a person, feeling, trait, place, outfit, action, whatever, that gets you going. Whatever takes you from not being in the mood to being in the mood.
‘Kink’ is a reasonably general term that covers any sexual proclivities that could be seen as unconventional. It comes from the idea that one's sexuality deviates from the norm—rather than a straight line, it has a bend in it. Costumes, role play, BDSM—anything in that kind of area could be considered a kink, but so could plenty of accessory-free activities.
It’s quite a nebulous, floating term, more about an approach or mindset than rigidly defined rules. One person might consider certain behavior utterly unremarkable while another might see it as shockingly unusual. Even a generation ago, some of the kind of stuff that is now seen as fairly pedestrian would have been seen as pretty outre. Some people will casually try anything and people for whom anything other than p-in-v is a real “Hold the phone!” scenario.
Until relatively recently, kinks were reasonably wilfully misunderstood, treated in the same kind of way as much more dangerous behavior. BDSM, for instance, was seen as a ‘paraphilia’ rather than a kink, grouped by psychiatrists with desires to perform non-consensual acts. This should go without saying, but there is a world of difference between consenting adults experimenting with each other in the pursuit of pleasure and people harming others against their will.
Technically a fetish is a sexual fixation on a certain object or act that is necessary for a person to achieve sexual gratification – if you enjoy x, y, or z, that might be a kink, but if you can’t get off without your y being x-ed by a z, that’s a fetish. A fun thing you try every year on your birthday? A kink. Can’t get in the mood without being yelled at? A fetish. Kinks are employed to enhance an experience, fetishes are integral to them.
Another way a kink becomes a fetish is if the other person can be removed from the equation – if you are turned on by the shoes alone, for instance, and don’t need anyone to be wearing them, that’s a fetish. There’s also ‘partialism’, where one particular body part is the object of that fixation and seen almost as being isolated from the rest of the body.
There’s a huge amount of crossover in all of these things – a fetish is a kink, while not all kinks are fetishes – but being able to clearly describe what works for you seems like the best way forward for everyone. Enjoy!