A sweat soaked scrotum that may or may not be the result of sexual activity. For example a homeless tramp would probably not have sweaty balls due to slappage against a females' arse.
Tramps suffer from sweaty balls because they dont wash.
Most plumbers and builders have sweaty balls due to the nature of the job. If your nuts have been hammering at some slappers arse for half a day they will definitely be sweaty and masturbation always produces sweaty balls.
Homeless man: "Can I interest you in a copy of the big issue"?
woman: "Oh OK"
Homeless man: "Can I just say you look beautiful"
woman: "get your sweaty balls away from me, you stinkin tramp"
big fat slapper:
"Fuckin ell, that was a rogering you just gave me and no doubt about it. Eh fuckin ell pour some water on your pubes theyre on fire"
"Oh that isnt fire, thats steam pouring off my sweaty balls"