when you leave a soda cup from a fast food restaurant, containing only ice, sitting overnight and, in attempt to drink it the next morning, you realize it's a nasty combination of slight drops of soda, and the disgustingwater the use for ice
dude, I woke up the next morning looking for something to drink, and all I could find was day-after water
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.