Deriving from a "vegetative" state often used in the medical field, it is a state of total physical apathy, usually on a couch or bed with music or in front of a TV; influence of drugs aids but is not essential to the meaning of the term.
The earliest media use of the term "veg out" originates from the 1990 film Pretty Woman where Julia Roberts says: "Let's watch old movies all night... we'll just veg out in front of the TV."
I'm going to spent all of Saturday to just just veg out on my bed listening to Radiohead and Coldplay.
I wasted a whole Friday night vegging in front of the TV.
the art of being a stoned couch potato.
i just vegged out on friday night!