Each dude takes one naked barbie doll (male or female) and attempts to cover the most surface area of the doll in semen, and the loser has to show it to a parent or guardian
Dude 1: I had to show my mom a cum covered barbie doll Dude 2: Bro wtf why?!
Dude 1: I lost at splatoon
To shoot semen. To cum in excitement. To jizz. Etc.
Derived from the Nintendo game "Splatoon", which is actually about humanoid squidpeople who shoot each other with paint. Not long after the game was shown off, people quickly began using "splatoon" as a verb, as a synonym for jizz.
I just splatooned in my pants when I heard about that awesome new Nintendo game!
You just got splatooned all over.
me: mate i got this game where you are a squid and spray bodily fluids everywhere its called splatoon
my mate: mmmmmmmmmmmmmm
Me: you shoot ink, not cum
my mate: why, it's a children's game. you should shoot cum
me: woomy yay yay