Of body parts not covered by a swimsuit, which do you find most attractive or arousing? I've heard of feet, armpits, legs, hands, and of course my own answer (see comments)
Striking facial features. eyes, smile, nose, even haircut. Applies to men and women. Also, I have really started to notice when a girl has her makeup and eyebrows on point. And even though it's covered by a swimsuit, the silhouette of a nice butt makes me double-take.
Hair - I doubt there's a heterosexual man alive who doesn't love women's hair. Personally, I like it glossy and black - which is why I've liked so many Indian women since I was about 12.
I've also got a thing about well-sculpted noses. I honestly can't understand why people have surgery to get one of these ridiculous button noses that make them look like a shaved pug when they could have a proper, statuesque nose. Edith Sitwell, for example - she knew how to wear a nose properly.
The most arousing and attractive part of any person, however, is of course the brain.
People really don't talk about noses as much as I would have thought. A strong nose says "Look at me, I command your attention".
My vote will go to the neck since you said covered... but I am visual and touch so I am a lot about shapes of the human body... the curves. The shape and curve of a back. And in college this GF liked to suck my eyeballs when I closed my eyes... talking about erotic in front of everyone... oh the 70's. A Lady with a Long neck suits me fine because I have a Long tongue.
A woman with zero tattoos is an instant turn-on, and if she has cute feet and takes good care of them, that works too. Also nice legs are important, as is a somewhat flat stomach. I also love the little dimples women have over their butts. I'm gonna say that's definitely in the top 3 for me.
The 'look' in the eyes with voice modulation and emphasis. Parts are superficially attractive too but nothing causes a higher degree of arousal in me than how a woman expresses herself and a look in her eyes that is consistent with it.
It can be a captivating, seductive form of music. If 'parts' happen also to be in concert, all the better.
I got a thing for tongues and the whole mouth really and smaller petite woman and I guess, I like all of the outside if it's balanced. the mind is the most arousing but I have to be physically attracted. I really like what I like and always have in all things. that's really hard to answer actually.
A flat or slightly pudgy stomach is extremely attractive to me. I'm an absolute sucker for a pretty face though.
My choice is necks. I think Freud would call me orally fixated, since I focus a lot on what my mouth could do. The somewhat bothersome thing is, almost everyone has a sexy neck. It makes it hard to focus sometimes lol. Fortunately, I've found someone who will let me do basically whatever I want with his neck lmao (just one of the many reasons we love each other).