how do I tell dad?

I was confronted by my mom last night about telling some one at church about cutting; there stuff she doesn't understand. Understandable. She noticed that I have told her, Tyler (my bro), Priscilla, and this friend and was wondering why. Why can't  I tell dad? Am I wearing this like a badge of honor now? I did after all, go to great lengths to hide the fact that I cut. why the sudden shift? Understandable questions.
The first one I want help with myself, Why can't I tell my father? I mean, it should be simple right? waltz into the room and say, "Hey Dad, i'm a cutter! you're daughter inclined towards self harm!" *head desk* I would be an Idiot if I did that, I think. I've told everybody else that needed to know, why can't I tell him? I think the answer is that I tell those I love, and it's painful for me because I know it will hurt them, and it does or i tell others because I want to rattle some one I know (face to face). Dad, Is some one I love, but I don't get to spend much time with him, I don't know what he'll do, I'm afraid to tell him. He is meant to protect and guide me, but he couldn't protect me from myself, how do I approach my father about this?
Yes, I am the sort of person who would try and rattle some one. Before my parents knew I did go far to hide it but know that they know about it, I feel free to tell people. Some people more than others. Am I proud of it? not really. I told my friend and it hurt, it hurt me, and she hurts for me while others I can tell with no problem what soever. the reason? I don't always fit in. when we moved to my currant home we found a group of people with whom I do fit in, and that is good, but there are those with whom I still don't fit in and don't care that they were my friends at one point. Them I would tell with out a second thought, Just to shake them up, call it twisted vengeance.
Then there is the the ever important question, "If you were to have you knives back right now, would you be cutting again in the next 24 to 72 hours?" asked by my mom. The answer would be yes. Probably, I would. At the moment it's a battle I don't even really know how to fight. I know all the stuff about taking your thoughts captive and all that, but it's not something I think about in that way, I guess. I don't think about it like, "oh I'm going to cut I want to cut really bad" I do sometimes but not all the time. At this point it's more of a knowledge that given the opportunity  I would do it again.
So. yup that's about it. gotta go for now. see ya around. don't forget to sign the guest book if you visited. :)