Sexuality is a very complicated subject. It is composed of 5 components.
1. Direct arousal.
This can range from a tingle to full blown arousal. This feeling can happen independent of other feelings or it can happen with other feelings. I for example feel this when I see big b**bs or a nice b*tt. I think girls experience this automatically to all sorts of things.
2. Direct attraction.
This is like a pull toward a person. A person doesn't have to turn you on to be attractive. The attraction is directed more toward the person than say their body.
This picture does not turn me on, but if I look at each of the people, I might find them attractive.
Note: If you get rid of their faces it isn't as attractive:
I mean if I focus on their bodies it can cause a little bit of direct arousal (or vicarious body attraction, which I will cover in a moment), but the appeal of the original image is no longer there.
For the girls, an analog might be:
Supposedly each of these guys is attractive.
For equity, I will crop their heads:
Supposedly this is less attractive.
3. Vicarious touch arousal.
This is when you see something sexual and you imagine how it would feel. So like if you're a guy and you see a picture of male genitalia that looks like yours and a girl is licking it and you imagine the lick on you (or touching you), that would be vicarious touch arousal. Even people who do not experience sexual attraction typically experience vicarious touch arousal.
4. Vicarious act arousal.
This is when you see a sexual act being done and you can imagine yourself performing that act. If you're into literature maybe you read about performing a sexual thing (or having a sexual act performed on you) and you imagine doing it. When this kind of arousal is combined with direct arousal, the result is typically something that a person would masturbate to.
5. Vicarious body attraction.
This is when you perceive something attractive that is the body of a person. For example, I see the back of a girl and it's a hot back and I like it and I imagine that the person possessing said back would be attractive.
(This one might also involve direct arousal, but direct arousal without attraction is just a tingle and then you forget about it - you don't concentrate on it or think that you actually want to engage in sex)
But she might turn around and look like this:
Now for a guy:
It's basically the same thing, but a guy. Now he might show his face and it looks like...
But yeah, I'm not really attracted to them (in this case I am referring to the backs), I'm just attracted to something about them, but it's still attraction because the desire is concentrated on them. If the sexual desire was "diffuse" and not concentrated on a person, then it wouldn't be attraction.
Anyway, there are five components of sexuality. Direct arousal, direct attraction, vicarious touch arousal, vicarious act arousal, and vicarious body attraction.
These five component play out in interesting ways. For example, with guys, direct arousal on its own isn't that common, but girls can experience wetness from a variety of sexual stuff. A guy on the other hand might experience sexual feelings downstairs, but those feelings are often accompanies by sexual feelings upstairs as well. Like for example a guy might see big b**bs and look and feel a tingle (direct arousal), but also want to touch (vicarious bodily attraction). Or maybe a girl sees a waitress at a nude bar with her massive b**bs hanging out and her nipples covered in sparkles and she experiences some wetness (direct arousal), but she doesn't want to reach out and squeeze the b**bs the way a guy would (no vicarious bodily attraction). In this same situation, a guy might act on his vicarious bodily attraction by hitting on the bartender, but the woman would not.
If you break it up into these five components, it is easier to understand.