A sexual act; the act of ejaculation through self-flagellation onto one's own hand, tossing the ejaculate into the face of a sexual partner with a swift, comical motion.
Seamus' girl Brooke had the pink eye for a solid week, and everyone knew it was because of his webslinging fetish.
When a man ejaculates into his hand and then proceeds to "sling" the seminal fluid at a girl's face in a manner much like the Amazing Spider-man.
"This girl won't swallow, so I have to resort to web-slinging her instead."
male, meaning to masturbate and ejeculate
What are you doing in their little Jimmy?
Webslinging Mum, go away/
fingering two girls at once.
I went to the bathroom with jesse and chloe and i started to go webslinging them.