So here’s what I’m thinking.
Every person has a unique sexuality. We all like and dislike different things. We all find different things sexy. We all experience different things as sexual. We’re all attracted to different things. Those differences aren’t necessarily large – most (but not all) people think orgasms are fun, for instance. But the differences add up, so that you can’t safely generalise between people.
Now, the way my brain works leads me to want to be able to talk about these differences, and one of the first things I do when I want to talk about something is to start defining things. It’s a lot easier to say “I prefer milk chocolate” than “I prefer confections made from the bean of the cacao tree when they contain cow’s milk and a higher percentage of sugar than the milk-free varieties”. If you’ve got to explain what chocolate is every time you want to use it in a sentence, it gets really hard to talk about chocolate. And sex is a lot more important than chocolate.

So I’m thinking about the components of sexuality and I think one way of looking at it is to think about fetishes, kinks and squicks.
A fetish is something that must be present in real or imagined form in order for you to experience something as sex. That’s actually a really strong concept. A fetish isn’t something you like, it’s something that you need before you feel as though you are having sex. I think one’s own arousal, and one’s own consent, whether or not that’s been communicated, are pretty universal fetishes.
A kink is something you like, and that can be an object or a situation or an activity or pretty much anything. Anything you find sexy, that’s something you kink on. I kink on male bodies, on rope, on bondage, on penis-in-vagina, on certain hairstyles. None of them need to be present, but they’re really sexy. They turn me on. Every sexual person has kinks, because a kink isn’t necessarily something weird, it’s just something that turns you on. Most straight guys kink on breasts, and there’s nothing weird or wrong about liking breasts, but it’s still a kink.
A squick is something that turns you off. Maybe you find it disgusting or humiliating or stressful – in a bad way – maybe for no reason you can explain, it’s just unpleasant. But it’s something whose real or imagined presence is anti-sexy. A lot of people find urine to be an active turn-off, for instance. (The word ‘squick’ is drawn from fandom, where it means something that provokes any strong negative emotion.)

It’s important to note that these three components of sexuality have one big invisible counterpart: everything else. You take the world and you draw three circles on it, your kinks, your fetishes if you have any, and your squicks, and that’s not the whole world. There’s a lot of stuff outside those circles and those things are simply non-sexual to you. You just don’t care about them. If your partner wants to include them in sex you’re not going to care very much, because they don’t turn you off – but they don’t turn you on, either. For instance, I find chairs to be completely non-sexual objects. I don’t get aroused by the presence of a chair, but neither am I turned off by them. I just don’t care about chairs. If my partner want to keep a chair in the bedroom because he kinks on the proximity of a chair, that’s fine by me. Comversely, if for whatever reason he really hates chairs, and finds the idea of fucking in the same room as a chair to be a complete turnoff – we’ll get rid of the chair, and that’s fine too. I have no opinion about the chair, because the chair is not included in my sexuality.

I personally find this set of four categories – fetishes, kinks, squicks, and non-sexual things – to be really useful in understanding my own sexuality. It helps me to think about things, because I can classify the components of my desires and my fantasies and that in turn means I know what to do about them. If I fetishise X, then I’m only going to be sexually compatible with people who are happy to do X all the time, which means they either fetishise it themsleves, kink on it, or find it non-sexual but also non-intrusive. If I have a fetish for wearing socks while I fuck, that’s not going to be a major barrier to compatability, because even people who find socks uninteresting are probably not going to mind if I wear socks, especially once they know how important socks are to me. On the other hand, if I have a fetish for scat, that’s going to seriously restrict my options because involving faeces every single time we fuck is going to be unacceptable to a lot of people. But what if I don’t fetishise scat, I just kink on it? Well, that’s a very different situation. There are, I’m guessing, many more people who are happy to involve faeces once in a while, especially if anal penetration satisfies that kink for me.

So this way of looking at sexuality leads to some fairly simple compatability rules. You have to be okay with your partners fetishes, and vice versa, and that specifically means being willing to cater to that fetish all or almost all the time. You also have to be okay with each others squicks, which means being willing to avoid them all or almost all the time. And it’s probably going to help if you kink on some of the same things, and are willing to do some (for you) non-sexual things once in a while if your partner kinks on them.