A variation of a "Wet Willy" but where emphasis in the "Wet Willy" is placed upon saliva, the emphasis in the Steamboat variation is placed upon ass sweat.
"Hey Brian, don't Steamboat Willy me while I tie my shoe."
-Michael Norman
When a person takes a massive rip of a vape, and then blows it ont/into the other persons genitals while giving head.
Dude #1: Bro, I was fucking this fat chick Sarah, and I gave her a steamboat willy
Dude#2: The fuck is a steamboat willy
Dude#1: Just check the urban dictionary
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.