(NOUN): When you start writing someone's initials -most commonly your soon-to-be (hopefully) significant other- all over your personal property, and sometimes on others' personal property. Also, can be posted on social networking sites on your status (myspace, facebook, etc.) and make its way into the margin of your tests, quizzes, notes, worksheets, etc.
"So, today I wrote your initials on the front of my science binder."
"Oh no! You've reached initialization!"