Pack
Leicester slang for 'stop'.

Often used as a verb ('Pack doin' vat!') or an interjection ('pack it in!')

In the case of 'pack it in', the last syllable is often elongated when spoken by children or the mentally deficient, resulting in a long, whining phrase that causes the target of the command to 'pack' whatever it is that's annoying the speaker, out of sheer annoyance.
'Pack it in, will yoh?'

'Pack swearin', yer cun'.'