not "all caps" just when you use a capital letter at the beginning of a sentence. it's like being formal but being formal in a no formal conversation is weird. so don't :)
friend 1: "Hey want to go out tonight? I found a nice place. What you think?"
friend 2: "ig it looks nice but why are you talking with capital letters..? it's to formal and weird, go look it up"
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?"