How to display a severed head:

1. Decapitate your victim.
2. Skewer the head on a pikestaff. It should easily tear into the goopy brain matter.
3. Display the head at a place of your choosing. 
4. Watch while crows and magpies pick out the eyes and skin and bits and pieces of brain matter. 
5. Leave the heads as long as you like. James Mayne's head was “illegally removed” in 1754—nine years after it had been hung. 

No actual people were harmed for this photo. I'm pretty sure.