The proposed ability of a given human being to detect they are being watched via extrasensory means, also known as the "psychic staring effect". It could be argued that it only applies when said feeling is accurate, and it's hard to test whether this is a real phenomena or simply paranoia turning out to be true sometimes (a broken clock is right twice a day).
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.