Pinch And A Punch For The First Of The Month Meaning

(idiomatic, Britain, Ireland) Said the first day of a new month, accompanied by a pinch and a punch to the victim. The victim can then say 'A flick and a kick for being so quick!' accompanied with said flick and kick.

Example: 2009, Ellie Nielsen, Buying a Piece of Paris: A Memoir, page 208:
  â€˜Pinch and a punch for the first of the month.’ I nurse my wounded arm and look down at my giggling son.
  'You just hit me.'
  'No I didn't. That's what you do on the first of the month.'
  'Who says so?'
  He looks at me exasperated.