When you have been out in the sun for so long that your taint is mess of ass juice and ball sweat.
After his round of golf in 90 degree heat his pants were clearly marked with a sweaty-kevin.
A sweaty kevin is someone who is so sweaty at what they do people have to stop and reconginze how insanely sweaty they are.
Oh shit did you see that Sweaty Kevin. he was a sick fortnite builder!!