This was actually so long ago (approx 35 years!). I was still at school and living at home. We used to have a sheltered area behind our garage that had high barriers of either hedge or brick on three sides which i used to use as a sunbathing area as it was also effectively sheltered from the wind.
On occasions when my parents were away or were on holidays I used to take the opportunity to strip off completely in order to get an overall tan. In those days there were no concerns about skin cancer and I found the sun helped with my teenage acne, and it was recommended by my GP.
I remember the unavoidable thrill of doing something that was a bit unusual and thinking my parents would not approve if they knew. I suspect now that if they had known they probably would not have said much as long as I did not risk upsetting neighbours.
What was really satisfying was the notion that there was no other way I could think of communing as closely with the elements and nature than that, other than going out and hunting your own food! It was and still is strange to try to explain the feeling in words. A heightened awareness of the senses over the whole of the body, the sense that no part of the body is hemmed in by fabric and elastic, a sense of sensuous vulnerability and exposure to the elements.
I have never enjoyed indoor nudism in the same way, probably because there is still that sense of being sheltered, protected and enclosed by a building instead of clothes.
Any passing resemblance between me and a walrus is purely coincidental and the walrus has told me he will sue! ☺