More properley "Kirkby Kiss" (named after the charming village of Kirkby the location of which is close to Liverpool) It pertains specifically to a headbutt administered to any unfortunate person who might happen to cause offence, or raise the ire, deliberately or otherwise of another. It is usually quick, bloody, painful, eye-watering and usually results in a complete capitulation by the unfortunate recipient.

A slang use for a punch used mostly by chavs