Disclaimer: None of the characters are mine, they all belong to the almighty J K Rowling =]

1
You are, quite frankly, my dirty little secret. They say the line between love and hate is fine, you straddle that line in a manner that makes me want to just...well, let's say it would push the boundaries of both pleasure and pain.
If anyone knew about this dangerous little liaison, imaginary as it is, I would lose everything. My dignity, my social standing. Everything.

But, oh Potter! The things I'd like to do to you!
I blame my hormones. My raging, adolescent boy hormones. My difficult situation. Confusion. Angst. How very tender.
I like to imagine you feel the same way about me. Maybe more...tenderly. Maybe not. You're so full of anger, frustration. You have to blow off steam somehow, surely?

You'd hate it. What we were doing. Me, yourself. But you'd want it, need it like I do.
We're very alike, Potter. Just on different sides of the fence. Good, evil. Love, hate. Very thin lines.

I'm actually really pissed off with you. I've came to realise what you've been doing with that filthy fucking dog. I see how he tries to ignore you in class, make it less obvious, but I followed you last night. Midnight. Room of requirement. You, him. An hour later, you emerged, separately, with sex hair. I wished it was me.

The only thing that makes me feel better, and worse of course, is fucking your dirty mudblood girlfriend. Feels like I'm fucking you, if I close my eyes. She always leaves in a hurry.

2
Oh, Harry. I wish I had the courage to tell you. But it's such a dirty little secret.
I'm so, so sorry. I don't know what the hell is going through my head, every time I sneak down to that dungeon, I wish I could tell you I was under a spell. Every time I tell myself, that it going to be the last time. I love you. I hate him. It seems so easy, but, god, I don't know; I just always find myself going back for more.
I feel so unclean. I know, he doesn't even want me, he just wants to get to you. Sometimes I think he just wants you. I'm sure I heard him gasp your name once. Nobody ever gasps my name, Harry. You close your eyes, both of you. You fuck me. Both of you. No love-making, like how it was at first. I know you're thinking about someone else. I feel so fucking dirty. Why are you even with me, Harry? Is it for status? Because people expect us to be together? Why?
I think you're seeing someone else, too. You're so moody. You'll never tell me where you've been. The library. Hagrid's. Patronus lessons. Patronus Lessons! Is that all Lupin's been giving you Harry?

3

Hermione, I wish I could tell you how sorry I am. I think you know my dirty little secret. Well, the latest one.
I need to stop this. Too many people are going to be hurt if we get caught. You already know though, don't you? Those imploring looks you give harry, the way you study our every interaction in classes.
Sirius. I dread to think what would happen if he found out that I'd been sleeping with his godson. He'd never speak to me again, never mind...anything else. I'm so scared. I'm sure Draco Malfoy is catching on too. But I also happen to know that he's in love with Harry, so that's leverage. I don't even know how it began. I don't know why it carries on. I mean, he's 17. He's old enough, but still, young enough to be my son. He's my best friend's son.
I was never attracted to James, so I'm not doing what Sirius does - tries to relive James through Harry. I just, I don't know. I was missing Sirius maybe, missing the warmth and security of sex, he made an advance, I let myself slip.
I don't know why I let it happen, I don't know why I let it carry on. I'm so weak.
Sirius, I love you, I'm so, so sorry.