' jabang' is common Hull (England Slang) used often by youths. Simply meaning 'would bang' (to have sex with).
bang sex Hull
Jabang (wudjabang) means- I would shag or would you like to have sex with me .If asked as a question, it would simply be 'wudjabang' . Meaning would you bang (have sex with ...)
It can also be used as a vulgar comment towards the opposite sex, for example :
Man : *sees a fit lass walk by*
His mate : *shouts undiscreetly* 'JABANG'. Meaning ( I would bang you ) / have sex with you.