It took me far too long to realize what I'd done.

When Ashley came home that night, I almost did a double-take at what she was wearing. It looked like she'd strategically ripped her shirt to show off as much as possible, and it was clear that she wasn't wearing any underwear...but to my surprise, as soon as walked through the door she blushed and went into her room to change.

For the rest of the night, Ashley looked like she wanted to tell me something. I could have pressed, I suppose, but I simply wasn't curious enough for it to be a priority, and so I sat back and decided to let her come to me.

It wasn't until later, when the pizza boy came to deliver our order and Ashley insisted on greeting him that she finally said something.

She returned to the lounge-room and immediately went bright red again. Her flannel shirt was missing three buttons - they weren't unbuttoned, they were actually gone. I'd find out later that in her haste to show off her cleavage to the pizza delivery man, she'd ripped it open with such force that the buttons had gone flying...before she'd manually unbuttoned the rest to show him her tits.

I hadn't even noticed she wasn't wearing a bra. Maybe I need to move "Awareness of Women's Apparel" up in my own cabinet.

"Jacob," she said, turning to me with a blush. "Can I talk to you?"

"Of course," I replied, trying to sound casual.

"In my room?"

"Of course," I said again, this time completely failing to sound casual.

If things were going as I'd planned, I was going to head into Ashley's room and she was going to flash me. Her need for exhibitionism would be so great that it would overwrite anything else...and she'd trust me too much to find it weird.

At least, that was what I hoped.

When I sat down on the end of Ashley's bed, I already had a hard-on. I'd been dreaming about this for as long as I could remember - seeing those perfect orbs of hers, those beautiful bouncing breasts that I've thought about so much...

But when my sister turned to me and started to speak, I realized that somewhere, something hadn't gone according to plan.

Ashley wasn't flashing me. She wasn't even showing off more skin than normal - as I'd been coming into her room, she'd been fishing around for a safety pin, and was now re-sealing the gap in her shirt.

She really just wanted to talk. And again, it took me far too long to realize why.

"Jacob," she said hesitantly. "I can...I can tell you stuff, yeah?"

"Of course, sis." I'd replied, at this point still hoping that this was a prelude to seeing her tits.

"I've been...feeling weird today."

"Oh yeah?"

"Yeah."

There was a long pause as I mentally willed her shirt off. I had no morality, and so you might think I was tempted to just reach out and rip it off...

You'd be right. But even with my Morality folder firmly at the back of my drawer, there were still priorities ahead of it - my sister's happiness, obviously, and my desire to keep on living with her.

And, of course, the all-important Sex with Ashley. If I screwed things up now, that was never going to happen...and that was far too much of a priority to risk doing anything that could screw it up.

Finally, she had the courage to tell me what was on her mind.

"Have you ever wanted to...show your body off?"

My eyes lit up. This was going exactly where I'd hoped it was.

"Yeah, I guess. I mean, it's pretty hot when people check you out..."

"Exactly!" she replied, far too quickly. "I mean, isn't it?"

"Sure," I said, trying to lead her in the right direction. "Even if it's to, like, a family member..."

"Ew!"Ashley said, and to my surprise, she sounded genuinely disgusted. "No, not like that. I just mean to...other people. Like, y'know. Strangers."

I was flummoxed. Like I said, something had gone wrong, and I had absolutely no idea what. So I just nodded, and let her speak.

"I just...I want to know I can trust you. You won't think I'm a freak if I talk about this kind of thing, will you?"

"Of course not." At least one of the folders I'd moved had done exactly what I'd planned.

"Today, on the bus, I just...I got this overwhelming urge to show off. To, like, the strangers on the bus."

"Okay..."

"And even the pizza guy. As soon as I knew he was coming, I couldn't stop thinking about it. I got all heated up at the idea, I just wanted to...I dunno. Is that weird?"

"Not at all," I said, trying to make the best out of a bad situation. It was quickly becoming clear that I wasn't going to see her tits, but even if that was a lost cause, I could build up some trust - lay some foundation for the future.

I started spinning my own tale of snap chatting with a girl, sending her pictures of my junk and getting shots of her boobs back. As I did, I saw Ashley's breathing getting faster and faster - it seemed that even hearing about exhibitionism was enough to get her turned on.

So why didn't she want to show me anything?

My sister thanked me for the talk, and I decided not to push my luck too far. I wished her a good night, and after leaving her room and going down the hall, sneaked back and listened at her door.

From within, I could hear the quiet but distinct sound of her masturbating.

...what was going on?

*

That night, after my folks had gone to bed, I got up and again entered the strange room full of filing cabinets.

Making a beeline straight for Ashley's drawer, I was relieved to discover that nothing had changed. Presumably everyone's priorities shift over time, but even though Ashley was obviously freaked out by her newfound need to expose herself, the Exhibitionism folder was exactly where I'd left it.

So why hadn't she been at all interested in flashing me? None of the folders in front of it should have had much of an effect - "Trust in Jacob" was the only one that I could see which could cause any kind of conflict, but if you want to trust someone, surely showing them your nude body is the best way of building that trust.

I withdrew the Exhibitionism folder, and briefly wondered what would happen if I didn't put it back in. Would she just become completely unaware of the concept? Or would it just be treated as an absolute non-priority?

Again, my lowered Curiosity was probably to blame for me not following that line of thought any further, and so instead I just opened up the folder to see what was inside.

Like many of the other folders, this one contained a few subfolders. In order, they were labeled:

-Exposure to Strangers

-Exposure to Acquaintances

-Exposure to Lovers

-Exposure to Friends

I found it interesting that Ashley was more interested in exposing herself to strangers and acquaintances than lovers, but the oddest thing about the contents of the folder was that it was missing "Family". I opened the "Friends" folder to see if it was nestled in there, but instead I just found the folders "Exposing Tits", "Exposing Ass", "Exposing Cleavage"...a folder for each part of the body.

Where was Family?

Ashley's new predilection for exhibitionism was useless to me, if I wasn't going to be on the receiving end of it. I went to put the folder back, but paused before deciding where it would go.

Ashley had become aware of her new fetish - she'd even used to to make sure that she could trust me. Moving it now might raise some questions in her mind...besides which, I wanted to make sure that she kept on trusting me. The more she trusted me, the less suspicious my actions would be.

But that wasn't what made me pause. My mind was ticking over...I had an idea.

No matter what I did, there was no way that I could make Ashley abruptly start having sex with me, not without her realizing something odd was happening. I had the ability to shift her priorities, but I couldn't erase her mind, or put thoughts in her head.

But...

If her actions weren't limited to just me, she was much less likely to find anything about it unusual. If Ashley started screwing everyone, I'd just be another name on the list.

The idea immediately made me a little squeamish. First of all, she was my sister - and as much as I wanted to have sex with her, I didn't want her to be the town bike. Secondly, the idea of sharing her with everyone wasn't particularly appealing. I knew I'd start to get jealous.

I probably should have abandoned the plan. Instead, a smile spread over my face.

The only thing stopping me at this point was me. And since I'd made Sex with Ashley one of my highest priorities, I wasn't going to let anything stand in my way - not even myself.

I tucked Exhibitionism back into Ashley's folder where I'd taken it out, right near the front, and crossed the room to access my own folders. It took me almost twenty minutes, but I managed to find what I assumed would cover jealousy - "Exclusivity with Sexual Partners" - and put it right at the back.

Opening up my own "Family's Well-being" folder, I dove into subfolder after subfolder until I found it - "Ashley's Reputation". After quickly browsing its contents to make sure I wasn't doing anything stupid, that too got relocated to the back of my own drawer.

Returning to Ashley's drawer, I considered just moving "Sex" to the very front, but I wanted to be more subtle than that, more careful. When her exhibitionist traits had appeared, she'd obviously noticed something was up - fortunately, she didn't seem to suspect outside influence (why would you?) but if she was suddenly sleeping with everyone in town, I feel like she'd notice something was up.

Instead, I moved up three other folders - "Sexual Health", which was alarmingly far back (I wanted to ensure that over the coming weeks, she didn't get any diseases, or get herself knocked up) and a section of her "Money" folder - specifically, "Short term wealth".

Exposure to Family was a tricky one. It simply didn't exist within her Exhibitionism folder, and I didn't have the faintest clue where to start looking for it. But I had a plan, and if all went well, the location of that folder would quickly become obvious...

Before I left the room, I opened my parent's drawers, and wondered what to do. I needed to make sure that they were okay with anything that Ashley and I did - my first thought was to adjust the "Children's Well-Being" folder to the back, but I immediately realized that could simply result in us getting booted out onto the street.

After a few minutes of thinking, I instead opened their "Social Norms" folder, and moved everything that could possibly relate. "Presentation of Children", "Offspring's Public Habits" - there were even separate folders for "Ashley's Job" and "Jacob's Job" - mine was significantly further forward than hers, I was surprised to notice.

I suppose as the only male, my parents thought it was more important that I do well - "Ashley's Boyfriend" was in a similar position to "Jacob's Job". My parents have always tried to treat us the same, but I guess it's a generational thing that they just couldn't avoid.

I was about to close the drawer when I had a thought. Within "Children's Well-Being", I found "Ashley's Sex Life" and "Jacob's Sex Life" - they weren't folders, just pieces of paper. On them was written all the stuff that you'd expect: "safe sex" (won't be a problem any more, Mom and Dad), "consensual", "fulfilling". I considered getting a pen and adding a few items, but I don't think anyone would remain calm if Mom and Dad started trying to get me and Ashley together.

Instead, I just moved them right to the back. Now, no matter what Ashley and I got up to, our parents wouldn't care.

Perfect.