Green’s Dictionary of Slang

yagga-yagga n.

[Cassidy & LePage, Dict. Jam. English (1980), suggest ‘Bungo talk’ substitution of y for r, thus ref. to rags and the person that wears them]

(W.I.) unmannerly behaviour.

[WI]Francis-Jackson Official Dancehall Dict. 56: Yagga-yagga behaving in an unbecoming way.