CMB in normal text can be used as follows: Hey, I just noticed your missed call. CMB when you are free, or when you have a meeting in 10 mins CMB when you are free. You can also hear it in family discussions such as, mom wants to speak with you, CMB. In the work place, one would write, Busy with a client, CMB asap. These are only examples of how CMB use to get quick follow-ups without having to go into lengthy explanations to maintain a direct communication channel. Know more about cmb meaning slang
