When one is extremely tired but must stay awake for one reason or another. In order to do so, they ingest a lot of chemicals (Red Bull, coffee, Mountain Dew, ect.) to keep going.
I am running on a little sleep and a lot of chemicals. I'm 9 hours, a venti latte and 2 gigantic red bulls into a 14 hour work day; at this point, I am only artificially awake!