It's a term used when working in the field. When the job is getting tough you have to get back up, dust yourself off, fire up a joint and keep working.

i.e. Joint Up, Spark up a J, Smoke em if you've got em.
In example when Land Surveying: The Party Chief might say, "Let's all j up in the low ground and get this job finished!" or "It's time to J Up!"
by The Frost Pin March 30, 2005
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Kyle - Hey man, I'm gonna play some Call of Duty. You gonna J up?
Mike - Yeah bro I'm down.
by dubstepmegusta August 20, 2011
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