One who is boorish, thoughtless, unsophisticated and ill-mannered. So ill-mannered, in fact, that they lack the courtesy to wait for an available urinal or commode, and instead elect to micturate in the fuckingsink.
Christ, who invited that sinkpisser to the party? Last time he came here, he ate all the buffalo wings and wiped his hands on the curtains, right after he put his cigarette out on the cat.
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.