When someone goes to the bar to order a drink but also orders a shot to take quickly and secretly. Often the person doesn't think other people notice but they do. They order the shot and take it at the bar leaving behind the shot glass evidence that the shot ever occurred.
Completely insane. Related to the term "nuts" (meaning the same thing) in the same way that "apeshit" is related to "bananas" and "batshit" is related to "batty." It is unknown whether the offensive terms were dysphemisms of the innocuous terms or the innocuous terms euphemisms of the offensive terms. Excepting "apeshit," all of these terms (including "bananas") have the same meaning, that is, "crazy."