the practice of stealing a person's seat when they temporarily leave it vacant. very common when there is an abundance of people with a limited number of places to sit.
"Don't steal my chair, bro, I call no chair pirating."
"I just got up for a mountain dew and he chair pirated me!"
"I just got up for a mountain dew and he chair pirated me!"
by xbridgebridge August 8, 2009