The first time that I wore Levis 505 Corduroy Jeans in the late '70s, I was hooked. I saw other guys wearing them, thought that they looked hot, and wanted to get a pair. They looked really good on me and showed off my ass, legs, and bulge nicely. The comfort was better than any other pants that I had worn. They fit like 501s, but cords are much softer and more pliable than denim, and they look a bit more dressy. I've been buying them ever since. IMO, cords show bulge detail better than denim. You can switch it up with different underwear or freeball, and get different effects. There is only one place that I found that sells new 505 Cords. Currently, there are black, dark gray, or brown available. Check out the link below:
Levi's 505 Regular Fit Jeans
For denim jeans, Levis 501s (botton fly) and 505s (zip fly) are my favorites. Whether cords or denim, Levis have a timeless fit that never goes out of style.