the act of stealing a friend's romantic interest (typically used by girls).
Ex. 1) Girl, you got cockjacked by your more attractive friend, Hannah.
Ex. 2) Hey man, your jerk-ass friend is planning on cockjacking you.
Ex. 3) Annabelle unintentionally cockjacks every girl when they bring hot dates around.
The action of hijacking / theiving / obtaining a penis to ride or pump in a sexual manner.
Rob is a cockjacker as last night he took advantage of Frank