Janelle and her younger brother, Jeff, spent summer nights in his bedroom. It was the only room in the apartment that came with an air conditioner. They’d watch TV or play board games and listen to music in there until someone crashed. 

There was a concert on late-night TV that they both wanted to see. It has been too many years since then to remember who was performing. As they were laying on his bed watching the show, it was drifting past midnight. The AC was cranking, and the room was getting cold. Janelle slipped under the blanket where her brother was already comfortable and warm. 

As Jeff started to drift into sleep, he rolled onto his left side. Janelle moved closer enjoying the warmth of his back. She draped her right arm on his and pulled herself in closer. She didn’t have an ulterior motive at the time. Jeff didn’t even mind the sensation. Janelle was soft and smelled great. They were close, anyway, and he didn’t have any impure thoughts about the position they were in. 

As Jeff tightened himself into a fetal position, his sister began to notice that his tailbone was hitting her right in her crotch. At first, she was startled and just felt a bit of a jolt, like licking a transistor battery. Jeff felt her jump a bit but he assumed that she’d fallen asleep and just woke abruptly and jumped.

“Was that one of those dreams where you’re falling?” Jeff asked. Janelle wasn’t unhappy with the sensation and made a point to move her pussy back to the spot against Jeff’s tailbone. He was lying still so this time she curled her hips to see if she could replicate the sensation.

Jeff felt his sister pushing against him. Still, there was nothing awkward about it. They’d been in physical proximity to each other during long car rides. Hell, they even held hands taking walks at times. No big deal, right?  

Janelle began tapping her slightly aroused clit against her brother’s tailbone. Again, Jeff felt her movement but didn’t suspect anything weird. Even still, now he decided to stay completely still and see what his sister was up to.

Janelle didn’t want to make it too obvious that she was liking the sensation as much as she did. She had to play this out carefully. She hung on until Jeff was completely still. She slowly started to grind her pussy softly against her brother’s tailbone. It felt amazing. Jeff could feel the motion. He was pretty naïve and sheltered and wasn’t sure what Janelle was up to. Still, he was going to go along with it and see what this was. 

Janelle was wearing denim shorts and a loose t-shirt. Jeff was wearing boxers. From his sister’s breathing, Jeff could tell that something was happening. Then, Janelle was trying to angle herself onto one elbow. She had her right hand on her brother’s right shoulder. She reasoned that she could open her legs a bit, and maybe the sensation would increase if Jeff’s tailbone made contact further down past her clit, and she was able to drag herself against him enough that her clit could almost crush itself at the highest point of contact. That strategy paid off as it heightened the sensation. 

From Jeff’s side, he could feel his big sister leaning up more. He knew that she was rubbing against his ass moving from beneath him up past his tailbone. While he wasn’t certain that this was sexual, he was certainly beginning to think it might be based on Janelle’s movement and breathing. 

After a few minutes of sliding her clit against Jeff, Janelle had her hand on Jeff’s right hip bone. She started to wonder if she could transition to straddling her brother while he was laying on his side and use his hipbone to the same effect. She’d heard no objections nor anything from Jeff since this “game” started. And we all know that when things get hot, we make decisions differently.

Jeff felt Janelle stop moving. Her breathing was still very irregular. He was terrified to say or do something that might give the wrong impression or that might make his sister stop what she was doing. He enjoyed the sensation, also. He didn’t want it to stop. Equally, he was now aware that his cock was hard as a rock. He didn’t want to acknowledge that and scare the shit out of his big sister either.

Then, Janelle delicately swung her right leg over Jeff. On his side of the bed, he thought that the fun was over and that his sister was leaving. Janelle steadied herself while straddling her brother and moved her crotch to just the spot where his hip bone was pointing at the ceiling. Both of them were still underneath the blanket at that point. Janelle had wrapped the blanket over her completely. She gently pressed her pussy against her brother’s hip. In her mind, nothing weird had happened yet. Nothing had crossed the line. She knew the sensation was something she wanted to prolong.

As Janelle’s pussy came down on her brother’s hipbone, she almost moaned out loud. She caught herself and managed not to. Still, this sensation was amazing. Jeff was skinny and the curve of his hipbone was almost the perfect length to grind against. At its peak, Janelle felt her clit crushing down against something really hard. Even through her denim shorts, the sensation was intoxicating and addictive. Meanwhile, down below, Jeff held himself in check and managed to keep his cock (which was sticking out, now) against his stomach and away from his sister’s leg.

Janelle resumed grinding against her younger brother. She leaned forward and placed both palms against the mattress on the sides of Jeff’s pillow. Now Jeff could feel his sister’s breath against his skin. He was shirtless so it was exciting. Her long hair was brushing against his face and body. As Janelle leaned further forward, Jeff could feel his sister’s round tits brushing against his arm. If he wasn’t hard before, he wasn’t sure what word to associate with his cock now.

As Janelle continued to ride her brother’s hip, she began dragging her pussy harder against him. She was pulling herself closer, using the mattress for leverage. As Jeff felt those massive tits brushing his shoulder, she began to slowly turn his head towards his sister’s silhouette. It was an amazing sight. The blanket has slipped down around her hips now. He could see Janelle’s hair hanging down. Her features were in total blackout. He could look down and see her ivory skin on her legs straddling his body. He could even feel her clit squirming between her and his hip. If only she wasn’t wearing those denim shorts the sensation would be even better.

As Janelle climbed to center her pussy at the peak of Jeff’s hip, her tits lined up even better with Jeff’s face. As they continued to bump against his face, Janelle prayed that wouldn’t stir him or interrupt what she sensed was building to an amazing orgasm.

Jeff slightly leaned his body back towards the mattress. It allowed him to face Janelle a bit better and watch this incredible view. As Janelle started moving back down and making longer dragging motions, Jeff eased his own right hand more against his upper chest. As Janelle’s t-shirt hung against him, he managed to hook his hand underneath the bottom of it without making it too noticeable. He was afraid to engage and have Janelle freak out and stop. By now, Janelle might not be able to stop. She was close to cumming.

As she ground her pussy harder, Jeff could now feel the bottom of his sister’s tits knocking against his hand. As he became braver, he moved his hand barely one inch higher up his own chest. That’s when he felt Janelle’s rock-hard nipple against his hand. It was like being struck by lightning. It took everything he had not to cum right then. He wanted to grab those tits and lick them, but nothing had given him the impression that Janelle wanted this to go that way. 

And then Janelle came.

She tried to control her breathing. She was gasping and hiccupping. She was covered in a layer of sweat that began to chill over as the AC continued to crank out cold air.

Jeff heard his sister softly whisper, “oh fuck!”

With that, Janelle climbed off her brother and sprinted out of the room. It was almost 4 AM. The concert was long over. Jeff lay there for a while before he got up and jerked himself off. He didn’t know quite how to register what had just happened. Still, he hoped it would happen again.