I couldn't believe how tired I was.

It'd been two days since I'd slept. Ever since I saw that damned picture ... I know you shouldn't click links in spam emails, but I think anyone would agree that this was a case of the punishment in no way fitting the crime.

As a straight female, I don't even know why I clicked on "teen lesbain sluts". It was like my brain momentarily lost control of my finger. Fortunately, when the image loaded up, it wasn't anything inappropriate - a good thing, too, because I was in the family room.

It wasn't porn, but it wasn't particularly interesting either. It looked like it had been made in MS Paint by a child; a series of overlapping rectangles, of different lengths and colours, with varying line widths. It wasn't interesting, so I don't know why it fascinated me so - I didn't even realize how long I'd been looking at it until my mother tapped me on the shoulder and reminded me that I had an early start the next day.

Looking at the clock, it quickly became apparent that I'd completely lost track of the time again, as I so often did on the computer. I closed the window, cleared my spam folder, and went to bed.

Normally I'm out as soon as my head hits the pillow, but tonight when my eyes closed, all I could see were the rectangles. Like I said, on the surface they weren't anything interesting, but the haphazard way they were placed somehow suggested that I was missing something, like there was a system or a code that I'd see if I thought about it for long enough.

It was like a puzzle that my mind wanted to solve, and I tried to remember everything that I could about the picture, my tired brain going over every detail again and again.

My alarm went off, breaking my concentration - apparently the picture was more interesting than I'd thought, because I'd lay awake all night just trying to figure it out. My early start was unavoidable, and so I struggled out of bed and (barely) managed to get through the day.

As soon as I got home, I was on the computer. I don't know what I was expecting, but google searches for "rectangles", "ms paint rectangle", "fascinating picture rectangles" and every other combination I could come up with yielded no results, or at least nothing useful. And "teen lesbain sluts" ... well, after 80 pages of porn results (even with the safe filter on) I was forced to give up.

I opened Paint and tried drawing it, but I'm no artist at the best of times, and a sleepless night doesn't help with that. All I ended up with was a mass of rectangles that - against all odds - looked even worse than the original image.

Despite the lack of similarity, I found it somehow comforting, and after staring at it for half an hour, saved it as my desktop.

Frustrated and exhausted, I ended up closing the computer and hitting the hay. Or at least trying to - like I said, I'm normally a great sleeper, and even if I'm unable to drop off straight away, it only takes a few minutes of tossing and turning (or a quick orgasm) to get me off to sleep.

I tried tossing and turning, I tried masturbating, but when I'm tired it's tricky, and after fifty minutes of playing with myself, I was forced to conclude that it wasn't helping. So for the second night in a row, I lay there without getting a wink of sleep. When I closed my eyes, all I could see was the rectangles; when I opened them, the darkness of my room.

Tuesday is my day off, so I didn't get woken up by an alarm. From my position on the bed, I just watched the ceiling as the sun came up and filled my room with light. I was too tired to do anything but lay there, and at 11am when my mother came in, that's how she found me - clearly exhausted, staring at the ceiling, not moving.

If my chest hadn't been raising and falling with my breath, I think she would have thought I was dead.

As it was, she clucked and told me to get up, and then when I didn't move, sat down and asked if I was okay.

Rather than get into it - how could I, anyway? - I told her I was fine, forced myself to get up, and sat on the computer in the family room, staring blankly at the rectangles I'd made.

It really shouldn't have taken as long as it did, but as soon as it occurred to me, it was blindingly obvious - Chrome has a history function.

I don't think our computer mouse has ever moved that fast - it took me a few seconds to find it, but as soon as the page loaded, my heart sunk. It was empty. The last site that the computer remembered visiting had been the previous day at 2am, and that was just my brother checking his email.

Sinking back in my chair, my brain was whirring as fast as it could in its exhausted state. For some reason, at 2am last night, my brother had deleted the computer's history.

Now, I'm not stupid. I was pretty sure I could tell you exactly why he deleted the history at that hour, but it was the last thing I wanted to be thinking about.

After a bit of googling, I downloaded a program that claimed it could help to recover the deleted history. It took a while to figure out, but soon I was confident I'd recovered everything that could possibly be recovered...

... and the picture wasn't in there.

Turns out that the computer only allocates a certain amount of space for history, and if you spend 80 pages going through pictures of teen lesbain sluts (not to mention the seemingly endless collection of self-shot naked girls my brother had visited) then it's not going to have room for something from the day before.

I was tired. I was miserable. But more than anything, I was furious.

One thing that most people don't know about me is that I have a temper. I'm normally pretty good at controlling it, but it really flares up when I'm tired. Like, it really flares up when I'm tired.

After two days without sleep, I was already at the end of my rope. When I realized that my brother had destroyed my last chance at looking at the rectangles again, I was angrier than I could ever remember being.

And so it didn't take long before I came up with a plan.

Three hours of trying to sleep had led nowhere, but a large part of me was glad. If I'd fallen asleep, I wouldn't have been able to get back at my shit of a brother. And right now, that was all that mattered: revenge.

Perhaps if I'd been thinking more reasonably, I would have realised that Ryan didn't really do anything wrong. But I was past that - all I wanted to do was get back at him, and so when I heard his footsteps go past my door just after midnight, I struck.

I didn't want to risk him hearing me, so I spent a full ten minutes opening my door, making sure that there was no creak. My journey to the family room seemed to take hours, but I was confident that my movement was completely silent. Besides, I wanted him to have begun his nightly routine before I struck.

As I'd hoped, when I sneaked into the room, he was facing the computer, oblivious to my presence. From my own early teenage years, I knew he'd be listening for the slightest hint of anyone coming, so he could quickly hide what he was doing, but I would have impressed a cat burglar with the silence of my motion.

Pictures of teenaged girls in bikinis flicked across the screen, and though the high back of the chair meant that I couldn't see, I assumed that his hand was gripping his hard cock. I grinned in anticipation - he had no idea what was coming, and I couldn't wait to see his face when I struck.

Finally, I finished moving across the family room. Standing above him, I could see that his face was gritted in determination, even as he struggled not to make a noise. He was uncircumsized, and so there was no lube to make a slapping noise as he moved his foreskin back and forth across the glans of his penis.

"Hello, brother." I said, trying to make my voice as sexy and seductive as possible. "What have you got there?"

The look on his face was priceless - he simultaneously tried to cover himself up, spin around, and close all the tabs he had open, and succeeded in doing none of the above.

"Don't be ashamed..." I murmured, my voice soft and silky. " ... maybe I can join you?"

"Sis!" he cried, his eyes almost falling out of his head as he saw what I was wearing. I'd been single for a while, but my ex-boyfriend had loved seeing my body in lingerie, and tonight I was wearing the prize of my collection - a bra that managed to lift my breasts and make them look twice as big as they did normally, and a g-string that showed off my ass, which I've long considered my best feature.

Of course, my brother couldn't see that from where he was sitting, but I knew he would before my revenge was complete.

I'd even shaved my pussy to complete the effect - I don't know if my brother was experienced enough to tell, but as his eyes raked up and down my body, I hoped he was aware of what the lack of stray hairs between my legs meant.

"Oh, come on..." I pouted, pushing my ruby-red lips out. "I just want to play..."

Perfect, I thought. My brother's erection had wilted slightly at the shock of being caught, but from the way it was plumping up once more, it was obvious that my performance was working, and he believed every word.

Without giving him time to respond, I knelt in front of him, and took his erection in my hand. It had been a while, but I was pulling out every trick in the book as I slid up and down his length, submissively looking up at him all the while. He still looked as though he couldn't believe what was happening, but his body was responding exactly how I wanted it to.

"What's wrong?" I said throatily, my voice no louder than a whisper. "Don't you want your sister to play with your cock?"

He just continued to gape, staring at me in shock as I leaned forward and wrapped my lips around his head. One hand pulled his foreskin down as my tongue swished around his head, immediately recognising the taste of pre-cum. An uncircumsized penis wasn't something I was intimately familiar with, but I'd seen enough porn to understand what would work best.

"Sis..." he gulped once more, but I looked up at him and held a finger to his lips.

"Sshhhh," I said, and he shut up. I brought my hand down and played with his balls as my head bobbed up and down on his cock, causing shudders of pleasure to run through his body.