Crowns (couronnes) if you find the "fève" in the "galette" (cake)!
usually on a wooden block.
The heads of important "traitors", were usually stuck on poles outside of the Tower of London, and sometimes could be there for years. Thankfully, Anne Boleyn and Catherine Howard had their heads...
The answer is that you probably shouldn't. It could get messy.
People with small heads are smarter according to studies.