Ag mode means: A state of laser-focused, no-nonsense, results-driven behavior where someone embodies the AG mentality completely. When someone flips into ag mode they cut the chatter, stop caring about perception,. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.