A uncommonly used putdown of the late 1990's that has since been replaced with more colorful expressions such as gaytard or dickhole. Basically it is used as a way to convey to someone that they are completely lame or a loser, but in a friendly way.
When Julie saw Adam's emo hair style, she exclaimed, "what a freaking lamatoid, who does he think he is kidding with that hair"?
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.