December had always been a problem for me. Gandpa spent the month at our house and left a few days after the new year began, and that meant he needed a room for himself. Now, when were kids, me and my sister would share a bed and grandpa would get the remaining room.
As we grew older, that continued, but we weren't small anymore and puberty had taken its toll on us. Now that I was 19 and my sister was 18, things were... different.
"Next rule: no jerking off this month," Chloe glared at me, looking up from the notes on her phone.
"Nuh uh, don't go changing that one again! Last year we agreed I could do it every other day while you went to the gym," I replied, showing her MY notes.
"Ok, but put the tissues in the trash," she said. "And I mean before I come back from the gym, Matt."
I nodded and we edited our notes.
"No using my bedroom as a drama control center."
"Our bedroom," she pointed out. Yes, rule number 5 dictated the bedroom belonged to both of us during December. I did not fully agree with that one. "And deal. No boyfriend this year anyway."
I clicked my tongue and she laughed. I had forgotten she was single, and that meant I had just wasted a rule.
"Could have told me. Or was this a trap?"
"I told you 5 months ago, idiot."
Ah, right, the incident. Now I remembered. How that guy had fucked up so badly, I would never understand.
"You're better off single," I said.
"Truueee. Next, no looking when the other person is getting dressed." And before I could protest, she added, "I'm not going back and forth to the bathroom with my clothes."
I looked to the side, where she had occupied a big chunk of the room with clothes and a mirror, and grimaced. "Sure."
We continued this for another half an hour, adding new rules and editing existing ones, until we were both satisfied. The list had started several years ago, when our egos had become too much for my -- our -- bedroom, and it helped keep us sane.
Not that I minded having Chloe there, obviously, but one month without privacy could be too much sometimes.
We both stood in the middle of our bedroom, Chloe barely coming up to my chin, looked each other in the eyes, and shook our hands to seal the deal.
December began the next day.
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The first night was a bit awkward, as we weren't used to sleeping in the same bed. Fortunately, our parents had bought a big one a couple of years ago when I had grown too much, so we could sleep comfortably.
I was in bed before Chloe finished her nightly routine in the bathroom, scrolling through my phone. When she came in, I had to turn away so she could change to her pyjamas. Funny how the not looking rule existed because Chloe had looked at me while I changed, not the other way around. Although, well, maybe I had and she just never caught me.
Not that I could be blamed, she was gorgeous, and the work she did at the gym really showed, especially in her butt. Damn she had the roundest of butts, big and bouncy and...
Ah, yes, another problem with sleeping on the same bed: erections. Now I would have to wait until it went down before I could even think of turning around.
Chloe pulled the sheet away so she could get in, but stopped in her tracks. I knew she couldn't see my current problem, but my heart still raced.
"Boxers only?" She asked.
Ah, that. "Rule 32, I can sleep however I want, just not naked," I replied.
Chloe mumbled something but got on the bed anyway, and I turned off the lights.
"Sleep well, big bro," she said.
"You too, lil sis."
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As always happened, we woke up the next day with her back to me, and my arm draped over her, holding her close to me. We didn't know why that happened, and we had even recorded our nights so I could prove I hadn't done it on purpose. But every day, for years, we had woken up spooning.
It was kind of cute, I had to admit. Comfortable and safe, as well. I could smell her hair from where I was, which I loved, and she always pulled on my arm so I would get closer, my body enveloping her small frame.
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The next day brought about some changes.
"New rule, I can sleep however I want, as long as I'm not naked," she said, before changing.
"We can edit rule 32," I said, but then I looked at her questioningly. "But why?"
"It's too hot in there! I sweated buckets yesterday with my pjs."
"Yeah, it's not as cold this year. So what are you wearing? Topless is included in the naked part, sorry."
She shook her head at the double standards and searched around for a while before picking up a shirt.
My shirt. The one I had used that day.
"Don't look at me like that," she said. "It's big and will cover me."
"Some underwear at least? Please?"
"Panties. I can't wear a bra to sleep."
I thought it over, but couldn't find any objection.
"Deal."
"Great!" She said, and she sniffed my shirt, to which I arched an eyebrow. "Yay, smells like you."
Huh. That... that made my heart skip a beat. Why was she smiling so much? I turned around so she could change, and certainly not to hide my blushing face.
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When she stood up from the bed the next day, my eyes widened. Yes, a girl wearing just your shirt was extremely hot, as I could now confirm. How the fabric fell over her breasts, then further down over her butt, hiding it by just a bit. That was something else.
She looked back at me in the middle of her stretch. "What's up?"
"Nothing," I replied, turning away.
"Hmm."
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That night, I woke up, and according to the clock on the table on the other side of the room, it was about one hour after I had turned off the lights.
To my surprise, I was already spooning Chloe, so I didn't move or make a noise, and I was ready to go back to sleep.
But then I noticed Chloe wasn't sleeping. How did I know she wasn't sleeping?
Well, from my vantage point, I could see one of her hands holding my shirt to her nose, while the other hand was in the middle of her legs, moving rhythmically. My shirt was bunched up at her hip, and I couldn't see any panties.
Oh yeah, and she was slowly grinding her big butt on my erect cock, separated only by my boxers.
Yeah, that was something I had never expected to see or experience.
My sister was masturbating right there in my bed -- our bed -- while she thought I was sleeping.
I couldn't even process what was happening, all I tried to do was not move or make a sound, even if I just wanted to contribute to what she was doing with her butt.
The next few minutes were some of the most excruciating ever, and I had never come so close to cumming in my boxers.
Eventually, Chloe clamped her hand on her mouth, quieting her moans, her body shaking as she orgasmed.
Holy fuck.
She fell asleep after pulling the shirt back down, and I forced myself to calm down and slept as well.
Maybe it was a one time thing. Surely she wouldn't do it again. I was going to ignore it and never think about what had happened ever again.
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She did it every day for the next three days. Every time, I would wake up to Chloe fingering herself while grinding on my cock. And on the mornings after she would be all smiles, a ball of happiness.
I couldn't even jerk off without thinking of her, and I had to stop myself every single time. She was my sister, damn it. Thinking she was beautiful was fine, jerking off while fantasising about her was not. It was wrong.
And yet, she had done much worse to me hadn't she?
I pondered that question for hours, and started noticing that I was looking at her in a different way throughout the day. The way she moved, smiled, replied to my jokes, or how she focused on the book she read that afternoon. It all seemed magical, otherworldly. Somehow, I had stopped seeing her as just my little sister, and had started seeing her as a woman.
And that flipped a switch in me.
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That night, I went to bed without my boxers. Yes, I was breaking rule 32. Did I care? No. Would she care? I... didn't know, but I was going to risk it and bet she wasn't going to complain.
Also, I kept the boxers at my feet, under the sheet. Just in case I needed to say that they had somehow slid down while I slept. Never break a rule without a backup plan.
My heart sped up and I could feel blood rush to my face, and to my cock but I calmed myself down, when she got back from the bathroom. I turned around, imagining her getting naked and putting on my shirt.
Chloe got on the bed, we said our goodnights, and I turned off the light. This time, I did not fall asleep, instead forcing myself to stay awake while making it look like I was asleep.
At the 30 minute mark, Chloe started her routine.
"Matt?" she called. I didn't reply, and remained belly up, feigning my sleep. She repeated this a few more times until she was satisfied I was asleep.
Then, I felt her hand pick mine up and start pulling me onto her. So that was how I had always ended up spooning her. The little rascal had been doing it herself this whole time!
I let her pull me onto my side, careful not to be too eager or too slow. I ended up spooning her again, and she maneuvered her body until she was comfortable. At this point, I opened my eyes, knowing that she couldn't see me with her back against me.
Chloe pulled the shirt she was wearing up, baring her butt, and she pushed her butt against me.
She gasped as she felt my cock touch her skin without any clothing in the way. She moved her butt around, feeling my cock, until it rested neatly inside her butt crack.
"Oh fuuuck," she whispered, half moaning.
I had to restrain myself from commenting on the situation, and also from just humping her.
Not that I had to wait much longer, because she didn't waste any time before she started moving her butt, grinding it on my cock. Her hands moved to their usual spot, one fingering herself and the other holding my shirt to her nose.
If the other nights had been hard on me, then feeling my cock move between her cheeks was hell on earth. Well, more like heaven, but since I couldn't just fuck my little sister right there and then, I had to stay still for the couple of minutes it took her to cum.
I still added a small thrust here and there, which elicited moans from her, and I pulled her ever so closer to me.
