Brother bear was bored.  It would be hours before their parents could come back with groceries and prepare dinner and this would not had been a bad thing if it wasn't because papa bear took with him the key to his secret stash of naughty magazines he would keep inside an old wooden chest in the basement, something Brother bear would had found out years prior as he was ordered to clean up the place begrudgingly.  He fantasized the day he found such trove of forbidden treasure and all its fantastic content which made him wild just remembering it.  That was the very first time his eyes would experience nude females of all sizes and shapes, young bears with ample breasts and peach-shaped asses that made him a bit weird in his pants.
Indeed, his penis would get hard and begin anxiously rising as his innocent eyes feasted for the very first time.  All these years he would wonder just what girls looked like, but for all his efforts he would get the blunt end of the stick...and a black eye for his troubles.  He scoffed at the idea of even wanting to check out some bratty girl who was as flat as a board when he could check out the curves and melon-sized tits of a much older and better looking female instead.  Now that he had his curiosity satisfied, what else was there to do back then?  Brother bear found out that his hand was suddenly stroking his erected cock; something he never knew would amplify his pleasure and would not stop as he savagely turned page after page of the porno mag.  Brother bear remembered the first time he climaxed that day, something that was heating him up even as he daydreamed, finding himself stroking his hard on once more.
However without the handy visual aid it would be difficult to please himself any further.  He had to get inspired and sadly it would be a while before he could do so.  Even when his parents would come back, he would still have to wait until he was truly alone in order to get to that key and the chest in the basement.  He would let out a sigh of disillusionment when Sister bear came into the room, all covered up in mud.  Brother bear quickly would stop pleasuring himself as she got in, covering his hips with a blanket.
"Are you still in bed?" asked an unsuspecting sister bear, making a face at him of disapproval.  Brother bear would be relieved that it was not because of what he was doing earlier to receive such reaction, but he still would retort in kind.
"Yeah? What about you?  You look like you had a wrestling match with a pig in a farm."
"Ha, ha, very funny.  I was out and happened to fall into a muddy bank that's all.  Unlike you I prefer to be active than being a lazy cub in the weekend."
Sister bear exited their room picking up a towel but not before sticking out her tongue at her sibling.  As she disappeared from view, a very annoyed Brother bear had images on how to get back at her.  Before long a certain image of a very lewd type would slide into his mind, one of seeing Sister bear quite bare, exposing all matter of bits Brother bear would know she had, but never had a chance to see before with his own eyes.  It was true that not long ago he would think seeing such young girls would not be as satisfying as adult ones on a magazine, and there was also the fact that well, it was his sister who he was now thinking of.  
However his needs were too much for the little horny cub who realized he had a score to settle with her anyway.  He could kill two birds with a stone so to speak.  It was settled, Brother bear would take action before their parents would show and the fact that he would just see her undress before getting into the bathtub meant that he would have all the time needed but he had to be fast while at the same time cautious that she would not find out.
Once he heard the bathroom door close Brother bear sneaked over in a quite matter, completely bare from the waist down as not to waste time in spying on her.  He would listen as Sister bear began humming from within the bathroom, something she would always do when dressing and on this occasion, undressing.  Brother bear smirked as he approached the door and stared into the keyhole.  There she was, sister bear bending over as she was finishing taking off her panties, giving away a good show to him that almost made him yelp in surprise, but had the control on not ruining the moment.  Before long he began stroking fast on his cock, still hard from the moment he thought about said dirty mags.  Sister bear was still moments away from getting into the bathtub, taking off her pink bow from her hair as slow as she would do.  Brother bear panted quietly into the door, masturbating and getting quite the pleasure on seeing all of her naked sister without any interruptions.
Apparently she had a whole lot more than what he at first thought, from her closed slit free of thick fur to her erect nipples on her otherwise chest.  Brother bear had thought that such lack of features on a girl would never excite him as much as an older female would, but now he would even consider running his paws all over her body...and perhaps a bit more.
Without realizing it Brother bear was now moaning out loud, his paws stroking faster as his eyes became fixated on his sister's naked body.  Sister bear turned her head to the door, hearing all the commotion as she approached it.  As the female bear cub opened the door to see who was behind it, she would let out a sharp yelp encountering her brother stroking in front of her, moments before him letting out an audible scream of both pleasure and surprise at seeing her naked body right in front of him, all covered on his young, thick cream.  Even after being found out he could not stop, jerking his erection vividly as he kept squirting all over her flat chest and face.  Sister bear did what she could to cover against the sticky assault, yelling in protest.
It all stopped as soon as it started and sister bear remained slimed, a look of disgust and disdain at her brother who remained in front of her both panting and blushing, eventually letting out an awkward smile to convey his apology.  
"H-how could you?!  You are such a dirty pervert!"
Brother bear shoved her inside the bathroom and closed the door at the sound of the main door opening along with voices of their parents entering with the rustle of paper sacks being carried within.  Brother bear pressed an ear to the door listening while holding his sister with a paw covering her mouth, all while she struggled to voice her protests about what had happened.  Brother bear gulped as he heard footsteps nearing close.
Mother bear knocked on the door to the bathroom seeing that it was all too quiet and the bedroom empty except by everyday litter their cubs would make when home.  
"Brother, Sister, is any of you in there?"
"Right here mom, taking a bath with sister!"
"Oh is that so?  Well then you both get clean and ready, dinner will be ready in a few."
Brother bear let out a sigh of relief as their mother left it at that, both him and sister in the bathtub together and quite bare as well.  She would hold onto her brother, giving him quite the look of sass and a smirk to boot.  
"Alright, I'll keep quiet about what happened if you promise to have fun WITH me next time."
"Sister," Brother said, "I would not have it any other way."
They both kissed passionately within the bathtub, holding their bodies immersed in water while also running their paws on the many places both were so eager to explore.
THE END