Smizzle duty is one's obligation to undertake while having a smoke. It usually requires one to be smoking at the time. While smoking, the person should have all their senses tuned for any goings on nearby and should usually only stand guard in one pre-determined area. If something is amiss the person on smizzle duty should proceed to report his or her findings to anyone that cares. If nothing eventful happens, the person on smizzle duty should make a summarised report to no-one in paticualar, though this is optional.
Person 1: "Let's go out for smizzle duty"
Person 2: "Nigga whaaat?"