Teaching My Sister

My sister and I have a very special relationship. Emily is only two years younger than me, but she has always really looked up to me and tried to spend as much time around me as possible, even sleeping in my bed most nights. I love spending time with her, too, so I always let her hang out with me in my room all day and hop into bed with me at night. Our parents are aware of this behaviour, but never saw it as wrong. They are glad their children have such love for each other.

So my sister and I continue to be especially close to each other, even today at 10 and 12. As we grew, we started exploring more ways of getting close, and found we really enjoyed cuddling. Emily could be my little spoon and hold my hand for hours, just talking with me in dreamy whispers about nothing in particular. We'll often cuddle when we're sleeping together, which is especially intimate as I'm usually wearing just my boxer shorts and my sister a T-shirt and pyjama pants, which turned into just a pair of panties as she got older. I never really saw it as something sexual, but did notice that sometimes she would give me butterflies in my stomach like crushes my own age would, and I wasn't sure how to feel about that.

I got so comfortable with Emily just being around constantly that I even change in front of her. I started doing it when I was 7. One morning Emily and I were hanging out in my room, as usual. She had already changed into her clothes for the day, laying on her stomach in my bed in her peach T-shirt, with her little butt sticking up and looking incredibly cute in her jean shorts. Her socked feet pedaled carelessly behind her as she watched me play video games, still wearing the superhero boxers and loose black undershirt I had been sleeping in. Suddenly, we heard our mom call from downstairs "Are you guys ready to go to the fundraiser?"

Oh crap! I had forgotten about a fundraiser luncheon for my sister's dance classes that we were going to. "I still have to change!" I yelled through the closed door.

"Well hurry up. We're leaving in five minutes," my mother replied.

I turned off the game and jumped up, dashing over to my dresser. Then I noticed that Emily was still lying on my bed, looking up at me with big, innocent eyes.

"Um, I'm about to take my boxers off. Aren't you going to leave?"

"Do I have to?"

I tilted my head. I had never really thought about it before. She had seen me in my boxers so many times before that it almost didn't feel like it would be that weird. But then again, it's not like I had any nudist tendencies; undressing with anyone else around was a little bit weird. I supposed she could stay if she wanted to.

"I mean, I guess not," I replied nonchalantly.

"Cool. I think I will stay then," my sister replied happily. Then, smiling slyly, "Don't you have to hurry?" She could be pretty sassy for a five-year-old.

But she was right, so I hurriedly took off my top and casually let my boxers fall, momentarily standing fully naked in front of my sister, whose eyes were wide with childish curiosity. She had a side view of me, with my back slightly turned towards her, so she probably couldn't see a lot of my penis, but I could definitely feel her gaze fixing on that area. It only lasted a little while though, as I quickly pulled out a fresh pair of boxers and pulled them on, although Emily probably enjoyed watching my little wiener bounce as I did that. Then I got dressed the rest of the way, and we went downstairs, never feeling like it was weird or anything. From that day on, any time I would be naked in my room, Emily would just hang around casually. I know she got really excited every time she'd get to see me naked, though. Despite all this, she never changed in front of me, and I secretly really wanted her to. We've never talked about it and I couldn't ask about it for fear of freaking her out.

Eventually she got bold enough to start asking questions about my "thing" as she called it.

"Where does it go when you sit down?"

"Is your pee stored in your balls?"

"Why are a boy's balls so sensitive?"

I answered her questions to the best of my abilities. It gave me an excuse to be naked around my sister and show off my dick to her more, which I came to really enjoy, in a couple ways. While it felt good to educate her and correct some misconceptions she'd heard, there was also a certain comfort in knowing at least one girl really liked my naked body.

I'm not sure if our parents knew any of this was going on, though I'd assume (and hope) not. Their bedroom was downstairs and both mine and my sisters were upstairs, so they'd just stay downstairs most of the time and shout for us if they needed us. We never had any problems with one of our parents walking in on us cuddling or me naked.

Eventually, Emily started to notice changes in my body. One day when I was in my room after a shower deciding what clothes to wear and just letting my towel hang over my shoulders she asked "Why did that hair start growing above your thing all of a sudden?"

I felt a weird feeling in the pit of my stomach. I was suddenly confronted with the fact that as both of us continued to get older and go through changes, our little lessons might start to get less innocent and deal with some stuff that I wasn't even that sure about.

"Well, Em, I'm starting to go through puberty. That means my body is going to start changing. Growing hair in more places is one way a boy's body changes in puberty."

"Oh."

There was a tense momentary pause, then my sister asked "What are some other changes that happen?"

"You'll see," I replied with a smile. Emily seemed satisfied by that answer, for now, and smiled back, though slightly apprehensively. Situation defused, for now. I didn't particularly feel like having "The Talk" with my sister. Though I felt I would end up teaching her about these things soon enough, anyway.

Recently Emily saw me with an erection for the first time. I came back into my room after a shower and since it was a hot day and I was still drying off I decided to just hang out in the nude for a bit. Emily watched without reaction from my desk chair as I set my towel down on the ground and sat on it, grabbing my video game controller and resuming the game I had paused before my shower. I brought my back to the side of my bed and spread out my legs to play a couple battles in my RPG game while the last of the water from the shower dried. Completely unnoticed by both my sister and me, I was quickly developing a random preteen boner as I was doing this.

When I felt dry I paused the game again and got up. I could tell by the characteristic buoyant bounce I felt from my member that I had just exposed myself in a totally aroused state to my little sister. Her eyes grew wide and she exclaimed "Whoa! Why is it hard like that?!"

Oh shit. This was actually happening.

"Okay, well, see... This is called an erection," I began to explain, gently bringing the volume back down from her level as I spoke to make sure our parents wouldn't hear. "And it's just a thing that happens to all boys sometimes. At all ages, but it gets a lot more common in puberty."

Emily seemed totally cool with what she was hearing, and her expression had turned back into the wide smile she always got when she was analyzing my body in a new way. "Okay, so... Why, though? Like, what's it actually for?"

"Well, it's usually for..." I struggled on how to word this in a way that would make my sister understand without risking teaching her any new words since I had no idea how much she really knew about this stuff. "For older guys, they get one when they want to make a baby."

"Oh..." I saw my sister's face drop as she realized the real implications of this new discovery she'd just made about the male body, and possibly graphically imagined sex for the first time. "Oh."

Then, I quickly added "B- But, most of the time it's not about that!" I don't want her to think I got one because I was thinking about having sex with her. Or worse, the elf girls in my game. "Most of the time it just happens randomly! And I have no idea why that is, but it's totally normal."

"Okay..." Emily's shock was fading back into an honest curiosity. "So, if you get them all the time, randomly, how come I've never felt it in your underwear when we're cuddling?"

"Because I hide it from you. I position myself so that it doesn't rub against you."

"I see..." my sister replied, with a note of tension hanging in the air for a long while, like she wanted to say something else, but wasn't sure about it.

Eventually, she slowly let out the words, "I mean, you don't have to."

Now it was my turn for my eyes to grow wide. I wasn't sure what my sister was implying but if it was what I thought it could change everything. Realizing that she may have crossed a line, my sister quickly started explaining.

"I mean, sorry if that's really weird. I just didn't want you to feel like you had to hide it. If it is, y'know, just a natural thing or whatever. I-" she paused for a moment before surely enunciating her last sentence. "I just wanted to make sure you were comfortable when we were cuddling."

I was surprised by how worried my sister seemed that she offended me so I tried to reassume a neutral expression before saying "It's okay, sis. I just wasn't really expecting you to say that. But I get it, now." I thought for a second before deciding it was probably okay to say "It's good to know I won't have to hide it if it happens again when we're cuddling."

My sister had seemed unsure, but with my last words her lips started to curl back into her loving smile.

"Okay, okay. Sorry about all that it's just... This whole thing just kinda took me off guard."

"Yeah, me too," I responded dramatically, and we both laughed. My erection having faded by now, I finally got dressed and went about my day. My conversation with my sister had seemed to end at a point of understanding, but I was still replaying the words through my head all day.

I had already dozed off that night when Emily jumped into my bed to cuddle. I awoke to her panty-clad ass and bare back, as her t-shirt had ridden up when she laid down, pressing against me.

"Hey, Em," I whispered.

"Hey," she replied quietly. I could hear the smile on her face.

I wrapped my arms around her and pulled her tight into me with made her let out a tiny yelp of delight, which turned into adorable giggling. I loved the feeling of her body shaking against me. And there was no denying it this time, I was getting aroused by it. I felt the bulge in my boxers slowly grow and was about the shift my hips back away from Emily when I realized this was the perfect time to see if she had really meant what she said earlier. I quickly took one hand off of my sister to reach down and pop my now fully-hardened rod up to the top of my boxers, so it wouldn't rub all the way up my sister's ass. I thought that might be an extreme way to introduce her to touching it. I let it rest across her back, just above her waistband.

I let my body come back against my sister's and felt my hard cock pressed between our bodies. I heard a light gasp as Emily realized what she was feeling. Then, she started subtly wiggling. Not to stimulate me, but just to get a better feel for the size and hardness of my member. It still did stimulate me, however, and my erection grew to a level I didn't even know it could, getting even bigger and straining against my boxers. Em let out a wordless whisper of impressed surprise at this, and I was worried she'd get scared, but after tensing up for a second she relaxed again and let my rock-hard cock sit comfortably between us. We casually spooned with my cock against her bare back, only my boxers between us, and I felt a love for my sister like never before. Eventually, my erection went away, as they do, and Emily and I drifted off to sleep, only to have a similar experience with my morning wood several hours later.

Since then letting my penis get hard and not worrying about how it rubbed my sister or the effect that rubbing had on me became a normal part of our cuddling routine, and Emily's gotten pretty comfortable around my hard on. Things never evolved past that.

Until last weekend, that is...