intravenous injection of drugs into one's jugular vein, located in the neck.
since it's so hard to jug yourself, assistance from another person is often required. usually the person using has to lay down and hold their breath, in order to puff out the veins; someone else will then do the injection for them.
person 1: "what the hell are you doing?"
person 2: "jugging my dope. all the veins in my arms are fucked."