look up any word, like b4nny:
 
1.
when one of your boys is getting a blow job in a car by a woman.
when somebody gets head jacks from that chilly chick.
by Spankey7289 July 11, 2008
 
2.
Giving Oral Sex to Male from Female or Receiving Oral Sex from Female to Male..(Female giving to Male) In other words getting some Dome or Head or Brain.
Man, last night I picked up this chick at the Bar and took her to my car and she gave me Head Jacks.

The other day my ol' lady gave me some Chilly Head Jacks!
by Bryan13 July 10, 2008
 
3.
in football when a player if facemasked, and his head is trusted backwards.
commentator 1: "did you see that face mask?!"
Commentator 2: "yeah, it was a total headjack - he could have got whiplash"
by Lauren December 24, 2005