Scandalousity is just a longer and sassier way of saying scandalous. It gives a better understanding that you are not taking the situation seriously. (It can also be used to replace the word scandal)
" I heard the teacher has been sleeping with her students"
" oh my gosh *gasps* the scandalousity"
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.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"