Using facebook as a means of distraction from studies or work that you should be doing instead.
Matt: "So hows that paper going for you so far?"
You: "Well, I haven't exactly started..."
Matt" "Are you serious its due tomorrow morning! What..have you been procrastibating?"
You: "No, but almost as bad. I've been procrasti-booking. I got on facebook for just a minute and now I've been procrasti-booking for the past two hours."
the act of putting of important issues, such as homework, by browsing facebook.
Mary: did you get that essay done?
Jesus: no, i spent all night procrastibooking.