(Verb) The phrase describes being a complete pile of shit, just drinking, smoking and playing video games or watching movies. Other activites can be done while "piling out", as long as the activity contributes to nothing, has no effect on the community, and is usually harmful to your overall health. This can be done individually, with friends or even strangers.
A phrase coined by skateboarders Peyton Dyer, Willis Kimble, David Gravette, and Seth Goler.
1-"Are you going to the house party or the bar tonight?"
2-"Na, i'm just gonna head home and pile out."