A state of comple relaxation and chill-out-ness. To get in a mind set where nothing can faze you.
person1: "jesus man ur stressing me out, work is doing my head in, I'm going crazy!"
person2: "you realy need to chillax before you burst a blood vessel".
When a bunch of dudes all chill together. Often it involves soda, PS3, fruitsplosions, pizza, and a box of springtime Oreos. The bro-chillin time runs late into the night. Always a good time, bro-chillin.