Nope. Never done it.
After age 18? No … but when I was 16 in West Texas, I had a friend take a photo of me naked in a Charles Atlas pose (I was a skinny, gawky kid, no one would really have mistaken me for Charles Atlas) and had another friend who worked in a poster shop at the local mall blow it up into a big poster. Then as a joke, I gave it to this girl who worked with me at a local restaurant. We both worked there part-time after high school, but we went to different high schools. She was a shameless flirt, and we got along well, so I knew it would be okay. And it was – she about died laughing when she unrolled it, as did everyone else at work. Ah, innocent times.
That was about 40 years ago. I suppose that poster could still exist, but it’s probably long deteriorated or been discarded.
Nope.
ETA: Actually, I don’t know. In my crazy college days, a bunch of us would go out to my buddy’s hunting property on weekends and drink it up good. One weekend, I was dared to pose naked on the hood of one of our friend’s pickup. I did it. I was lounging like a model, with one leg covering all of the interesting stuff. The picture existed at one time. I have no idea if it still does.
Yes. In the 70s I was asked to pose nude playing my bagpipes for a women’s calendar.
Yes. HUNDREDS.
I’m quite the exhibitionist, and I love creating amateur porn, then posting it online.
There are both still photos and video starting from 1994 up to just a few months ago that feature me with different women. Among them: an ex-wife, several ex-girlfriends, and my current lady.
And before anyone asks, yes, they’re each aware of the product, and the postings. I make it a point to blur our faces in both the photos and videos, and bleep out our names in the videos to hide our identities.
Yep.
I think I took a nude selfie within the last fortnight for my husband. Definitely within the last month
That’s just the most recent. Usually only when he’s away from home for a few days
No. A kind-of-ex sent me ones of her and was very clear that she wanted ones of me. I said that she’s welcome to send stuff to me but I in no way want pictures of me out there. Note: I did not talk her into sending photos to me.
Yes. My wife and I have stills and videos of one another;. I also once posed nude for my (former) best friend’s girlfriend back in college, and my wife had posed nude for some artistic nudes my stepdaughter did.
Yes.
Probably hundreds, but only from the neck up. Maybe a few from the waist up, when on the beach or in water parks, but none showing my manly bits. Never had the urge to, plus never had a camera with a big enough zoom on it 
Yes. Many.
Naked? Yes, I’ve been to a few nude beaches.
Explicit, showing the bits as the main subject? Or even shot as a “nude photo”? Heck, no.
Absolutely not.
If you count being in a bath with the lower half covered by bubble-bath, then yes, yes I have.
But no Full Frontal Nudity as far as I can remember.
No
Back in the day, my best friend had taken some very tasteful topless photos and shared them with me. I was impressed enough that I told my then boyfriend that, if he was interested, I’d be willing to do the same for him. He was, but somehow I never got around to it. And then we broke up. Meaning the best I can answer is almost, but in the end, no.
When one goes to a nude beach does one expect to have their picture taken??
I just took one but it broke my phone. So I guess no.
Like on clothed beaches, I’d take exception to anyone taking pictures of unknown people.
But since I - and my SO - bring a camera to take normal, innocent vacation pictures when I go to the beach, that has also happened on a nude beach. No big deal. But as I said, no “junk” pics.
My ex used to think it was funny taking pics of me in the shower or comming out of the shower. One time I was laying on the bathroom floor with a mirror trying to pop a pimple on my butt and she snapped a photo. This was before digital camers so I am not to worried about it.