when you put your balls into a girl's anus and you put your cock into her vagina and then lift up and pull your balls out slowly
I went over to Amir's last night and got blacked out drunk; then his girlfriend came in and let me perform a wet dog on her, my balls smelled like rotten eggs for a week!
The round kid at school or work that looks like a big wet dog thats just emerged from a large amount of pond water. Usually has a 24-hour 'wet' appearance.
youth 1 "Hey look it's Garnett!"
youth 2 "wet dog!"
youth 3 "hey wet dog!"
youth 4 "Garnett, do you knowyou look like a wet dog?"