The first time I used the word was approx 1968. I got caught talking to an adult and nearly said pussy and then tried to say wimp and it came out as "wussie". In later uses it was shortened to "wuss" for a less offensive slang word.
I used "wuss" as early as 1968. I may not have originated the word but never heard anyone outside my peers use it until several years later. I was talking to an adult(in 1968) and nearly said puss--. When i tried to correct it to wimp it came out as "wussie". Since this seemed acceptable I continued to use it as "wuss". This seemed to be the least offensive form of the word.