Pretty self explanatory. When you more than sad, but less than depressed, you are BIG sad. When you BIG sad, you cry very loud, hence *crying noises intensify*
You: OMG IM SO CLOSE TO WINNING!!!!
Mom: BRUHHH turn your computer off.
You: Why would I turn my computer off?
Mom: BRUHHHHHHHH I turns the wifi off LOL
You: NOOOOOOOO
Mom: LOLOLOLOLOLOLOLLOL
You: BIG sad *crying noises intensify*
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.