«Politics is a contact sport, and certainly heads butt from time to time,» he said. (nydailynews.com)
Right before the knock out is a serious head butt by Johnson and IMO it lead to the KO. (sbnation.com)
This breed tends to like everyone, but be particularly bonded with one person in the home and show that love and devotion by giving that person gentle head butts. (catster.com)