Tony Abbot deserved it (A)
https://www.theguardian.com/australia-news/2017/sep/22/man-charged-over-allegedly-head-butting-tony-abbott
2. Firmly cup your hands behind your attacker’s neck, making sure your arms are bent so you have full power!
3. Jerk hard and fast as you pull your attacker’s face INTO the headbutt, while you are headbutting forward full-force with the top of your head.
4. Repeat multiple times (if you don’t feel him instantly crumple), fast and hard, until the attacker is down.
(professional instructions via modern combat & survival)