A term that can be used to describe someone who is lazy, or even just stingy. A person who hogs all of their food, even if a starving person asks politely.
Wyatt: "I didn't have any breakfast, and Spencer is being Mentally Fat."
Spencer: "I'm not fat!"
Wyatt: "I said you were Mentally Fat!"
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.