A derogatory term for drug-users at dance clubs. Most commonly employed when describing Methylenedioxymethamphetamine (Ecstasy) users. The term itself comes from the fluid head movements done by those described; appearing as though their neck is made of jelly.
"Yes, Jason and I used to hit the clubsall the time, but we have not since he became a jellyneck."
Verb - Another way of saying you're bullshitting around, bored, or overall doing something other than what you're supposed to be doing.
First overheard during gym in high school while walking the track where the coach yelled out to the boys special ed class to quit jellydicking around and finish the lap already.
Hey man what are you up to?
Nothing, just jellydicking around at work.