When someone becomes more attractive to you when you haven’t seen them in a long time. Basically, your image of them in your head becomes more attractive.
Matthew: I thought you were over Terrry?
Sam: I haven’t seen him in a month, and you know what they say, absence makes the dick grow harder.
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.