brainface

A whimsical word used to describe someone who typically says something that alienates one or more of his/her friends on a daily basis, shouts random nonsensical words at awkward moments, tells stories that go nowhere and should probably stop one to two sentences before they actually do, makes references to world of warcraft knowing full well that no one in his/her social circle plays the game, and is frequently prone to bouts of dementia in which "every girl on earth is horny for them".

Variations include, but are not limited to:

Facebrain, Brainhead, Headbrain, etc.

when a male grabs his genitalia, gently squeezing, so the balls inflate, looking like a brain.