The most common thing that allosexuals (i.e. non-asexuals) describe with sexual attraction is an urge to physically be as close as possible to the other person. It also common to hear about a 'positive feedback loop' where reciprocated attraction leads to the attraction feeling even stronger.
It'll vary from allo to allo, but here's my cis male hetero experience. I am poly, with an ace wife and an allo girlfriend, and other occasional casual partners.
The trigger is almost always visual. My eyes are drawn of their own accord to their most feminine physical features. Usually the hips/waist curve. If she's not a current or potential partner I do my best to avoid eye contact, and mentally try to shut it down. You get pretty well practiced at keeping your desires under control after your teens, but if it's safe to secretly admire her, I might not try so hard. I'll imagine what it would be like to hold her, or what she might look like naked, or whether she might find me attractive as well.
If she's a partner already, looks become less important; it's all about touch. I'll pet her, caress her, kiss her. Casually at first, like as an invitation. If it's welcomed, our mutual sexual desire builds on itself. It's like a reverberating echo, if I feel the desire reciprocated, my own intensifies.
With mounting intensity, I need to hold her close. Skin to skin contact. There is literally no feeling in the world for me like feminine skin. It's a delicious feedback loop. I need to touch her more, everywhere. Sound takes a step forward in its importance, her moaning in pleasure. Clothes get in the way. I need to wrap her around me. Oxytocin and dopamine flood my brain.
It's intense as fuck.
As a demisexual, I will try to explain as best I can. Excuse the cake analogy, but it’s all I got. You can replace it with another food if you like.
It’s like when you see a cupcake that looks really really good and you want to eat it. It looks perfectly moist and that frosting is just so perfect I was to put it in my mouth to see what it tastes like. You can experience this desire whether or not you’re hungry (libido). You just feel drawn to it. Or it’s like seeing a really really soft, cute dog and you really really want to pet it.
So that’s attraction in general, and so sexual attraction is feeling that way about sex with a specific person. I remember the first time I felt sexual attraction to my now husband. It was just like when I saw a really yummy looking piece of food or a really cute animal, like a magnetic pull. But instead of eating a cupcake or petting a dog, I felt a desire to touch him sexually, and for him to do the same to me. As a demisexual, it was less about his looks and more about our emotional connection and intimacy. But still, it’s sexual attraction. Even when I’m not aroused or in the mood for sex, I still sometimes just look at him and want to squish his butt (or other things).
If you have never felt that desire, it might be hard to understand, just like it’s hard for someone who doesn’t like dogs to understand why you’d want to pet a dog, or a person who doesn’t like sweets to understand why you’d want to eat a cupcake. But I personally feel like all of these drives and desires feel very similar, just directed towards different things.
OK. Cis straight allo female here.
The moment that stands out most to me, was with a friend I had a deep, intense crush on a few years ago. He often wore heavy sweaters or flannels. One evening, I looked up across the room to see him taking off his sweater, leaving his t-shirt on. His neck was sweaty. My eyes literally could not look away. I wanted to lick his neck, wrap my hand around it, run my hand down his neck to his shirt where it stuck to his chest. It was this all consuming feeling, I felt it in my gut, between my legs, tingling and just very aware of this feeling to, for lack of a better phrase, consume him. Meld my skin to his.
Another moment, we were cuddling on the sofa. There was a vibe. Sexual tension. We nearly kissed, then looked away. Then looked back and kissed. And then we couldn't stop. I just wanted to touch him, to feel his hands on me, peel off his shirt, get as close to his body as I could get my body. It's very, very visceral.
I'm demisexual so my experience is different to that of an allosexual person but here's my grain of salt. Most of the time it's the feelings I experience for the other person (i.e love and feeling loved) that gets me going but I have moments here and there where I experience physical attraction (always tied to feelings of love, deep affection and trust).
For women, generally the curves of the breasts, thighs and buttocks, their general softness of form. With men, it's more directed toward the face; haircut, eyes, lips, jaw, neck, and collarbone, how they move, large shoulders. Skin in general and strengh in the embrace but the kind that makes you feel safe (men or women).
Aesthetically speaking, I can appreciate those too but if I look at it "right", it's like trying to imagine and feel how soft (skin wise), firm (presence/whole body wise) and warm (body heat) that person can be and wanting to hold them and touch them everywhere and be really close, envelop yourself in them and just be so close that at some point it devolves into sexual arousal. Sorry for the bluntness but I find myself wanting to kiss and lick them all over. It's a sort of pulling sensation from the chest in a way and heavy between the legs. And when unfilfilled (not being able to touch like I want) can get very constricting sometimes, like your own skin is too tight. But it's always a result of me being in love so that last part especially is probably different for allosexual people; I'm positive the too tight feeling I get is more an unfulfilled emotional need than a physical one. An unfulfilled sexual need is more irritating like hell than distressing (i.e anger and not sadness).
I heard an allo bi girl discussing the subject once and she said she walks up the street sometimes and just knows she'd be down to have sex with that person across the street like... now. But I can't relate to that, the most I get in these moments is aesthetic attraction (until they open their mouth and ruins it) so I wouldn't know how to describe to you pure sexual attraction or pleasurable casual sex. I've done it (long story) and it was sort of arousing in a very base physical way, in a 'someone's rubbing up against me right now' way similar to masturbation but there was no physical attraction there, mostly it was just mechanical, vaguely unpleasant and often disgusting afterwards so...
I think I actually only really feel sexual attraction when I really really like a person (which rarely happens based on visual appearance and never solely on that). I also feel it based on actions like kissing for a long time or making out or hugging and feeling their boner if they have one. Or stuff like that. Also sometimes it just happens when I realize someone is a really great person. I guess that just starts my thought process and results in me realizing that I find them very sexually attractive. It actually doesn't really matter that much how they look like it's more important how they act and what we do.
I have no idea how to describe that though, it's just that I know that given the right circumstances I'd like to have sex with them. And it's also the urge to do it and to touch and kiss them.
Well, for me, I'm very much into voices. I had the great privilege to know a woman with a deep husky voice. And in the interests of honesty, I found it very attractive to hear her talk. It feels like a rush to me. The first time, I felt quite excited by it and my heart beating a lot faster than it normally does.
It's a very physical feeling that kind of arises out of nowhere. I suddenly feel a surge of energy, like I want to go for a sprint; my body suddenly feels warm inside and I feel a tiny bit out of breath. I have this intense craving to have this person as close to me as possible, to cuddle them intensely, but cuddling doesn't feel like remotely satisfying enough. I find myself imagining wrapping my arm around their waist and pulling them against me and French kissing them passionately. Everything downstairs (I'm a cis woman, for context) starts to feel extremely warm, literally, and a bit swollen feeling, and I become unusually aware of that area of my body. If the feeling is really intense, which happens during times of high libido, then I might have the overwhelming need to masturbate if that person isn't sexually available right then.
Now, I can definitely feel milder forms of this, where these feelings are still there but significantly less intense. It's easier to notice them if I've felt strong ones recently. Sometimes romantic feelings happen simultaneously, sometimes not. Aesthetic attraction sometimes sparks it, sometimes not