In the early '60s, I bought my first square cut stretch bathing suit that was made from stretch latex, a similar material that was used for ladies girdles. I saw other kids my age wearing stretch suits and I wanted something different than the baggy swim suits that my mother bought me. The following year, I bought a square cut that was made from a knit material (can't remember the material). The knit was much more comfortable than the latex, but not as supportive. The latex would show a bulge, but held it closer to your torso than the knit. I liked the knit fabric better than the latex because my dick would stick out further from my body. As a young teen becoming aware of my sexuality, I liked to that people on the beach in Atlantic City could see my dick. The French Canadians wore swim briefs similar to modern day Speedos, not square cuts, and I really wanted one. I couldn't find them at any of the local stores. In the late '60s, I found my first brief cut swimsuit when I was in high school. It was black and I loved to wear it. I think that it was made from stretch nylon.
In the early '70s, I bought my first Speedo. It was white and royal 3/8" stripes made from nylon. The nylon had a slippery feel and I loved the brief cut. The following year, I got a Speedo Catalog that offered the choice of nylon or a new fabric, lycra. I ordered lycra and never looked back. Lycra has to be the nicest of all the stretch materials, especially after you've worn them a few times and they get broken in. A few years ago, I ordered an Aussiebum nylon suit. It was nice, but I was reminded of why I prefer lycra to nylon.