Interjection. More of being emphatic about one's manhood, expressing delight about an achievement (be it theirs or another's) or sometimes just a macho way of clearing one's throat.
An onomatopœia which describes the staccato, repetitive sound of automatic gunfire. Used in series, often separated by hyphens. Madepopular by the epic war movie "The Battle of Britain".
Flight Officer Archie (says generically, as new pilot is led to aircraft): "Spring chicken to shitehawk, in oneeasy lesson!"
All flight officers (in low-toned unison): "Dakka-dakka-dakka-dakka-dakka..."