When someone has ejaculatedon the back of another persons neck and starts slapping the person's neck with they're own dick while the semon is on they're neck.
When your (girl) friend asks to go on your shoulders, lets say at a concert or festival, and she isn't wearing any knickers, she subsequently gets the back of your neck wet, officially making you Wet Neck Sisters for life. A bond that can't be broken.
Getting your throat slit or shot. This is a common phrase used when rivals threaten the others with death threats. Rarely the comment is a hollow promise.
Fuck that jit fool, ima make the boys neck wet if he don’t stop playin.
Yo fool, back up you’re gonna get your fuckin neck wet!