Someone who cannot survive without constant attention from other people. Common sayings are "watch this", "look at me", "look what I can do", etc. See: Attention whore. From Rick and Morty episode "Meeseeks and Destroy", where a character named "Mr. Meeseeks" always shouts "look at me!!!"
This comes from the Loadout Community where a non-native english speaking player was attempting to ask about Canadian holidays and if, in fact, Canada had a day celebrating the "meese species" in chat. After some confusion it was discovered that he was asking if Canada had a day celebrating the moose. It snowballed from there and has taken over the entire community.
When A.Meesters tells a tall tale, then whilst informing others- even within earshot- adds more and more farfetched lies to the story until the point where he has lied about a lie. Oh, and theres always bisexual girlfriendsinvolved. Always.
1. Goddam it, stop your meestering
(Original Story)
Hey man! Just came back from the dentist's office. 2 cavities.
2 mins later...
Holy crap, I just came back from the wildest party, I went to *Insert random place here*, then I got totaly hammered and when I was walking back, I saw my ex-bisexual girlfriend and we smoked chop then we went skiing in July and then she fell asleep and I was bored so I went to the sewers and chatted with the teenage mutant ninja turtles. Splinter has a cold. Then a foot solider punched me and that's why my face is kinda numb. And I'm actually half eskimo in origin.