open neck 

This is where you discover some one with their chin up and you proceed with a karate chop to the neck while shout "open neck!" The person doesn't have to be with their chin up, they just need chin high enough to fit a flat hand in. You cannot "open neck" some one if they know you are going to do it or if they have their chin down a considerable amount. The whole idea about the "open neck" is supposed to be a suprise with a choke. Be careful if you decide to play this game, because it can keep going on for years to come.

"Hey, look at Shaun sitting there staring at the computer." *Nick creeps slowly behind Shaun, then moves to the side of him...*
"Open Neck!!!"
*BAM*
Shaun: "Uuuugh, you smashed my throat"

open neck by Nicholas Q August 27, 2006

National Open Neck Day 

A National Holiday where you slap people's necks on April 21.

Josh got his neck slapped on National Open Neck Day.

National Open Neck Day by liquid19 April 21, 2022

Open Up Yo Neck 

This phrase is typically said in a mugging in which the mugger will politely ask for your necklace or chain

"Ayyo Open Up Yo Neck!" *steals chain*

Open Up Yo Neck by Muggers anonymous September 6, 2020