When a man of small moral value leaves a large contribution of piss on your floor. Varying levels of severity are based on how many household objects were covered in the alleged Floor Nag.
Oh man, Lester got super drunk and Floor Nagged all over my vacuum.
Used by a person who is hammer drunk and trying to contribute to a conversation and show interest without knowing what the hell anyone is talking about or the location of his own feet.
Simply: "Yeah man totally, I have a concerndish"