"yaar maxxing" means: The deliberate, active practice of being the best possible yaar you can be — investing maximum effort into your close friendships, showing u.... This is a fairly neutral word with no inherent risk attached. There is no real cause for parental concern; it is descriptive vocabulary rather than something dangerous. If your child uses it, context will usually make the meaning clear. A brief, curious question about where they heard it is generally enough to know whether to follow up.