Uncle Rusty promised Little Bear on the night after him and Father bear finishes Emily's house he'd come visit. Come next summer Uncle Rusty visits the bear family and they welcome him with open arms. The two brother catch up on lost time while Mother Bear and Little Bear are busy in the kitchen preparing a feast for the entire family. 
Uncle Rusty stands outside the kitchens half open Dutch door, beckoning Little Bear over to him he asks , "Hey cub, you still got that necktie I gave you?".
 "Oh yes Uncle Rusty, I'll go get it!" Little Bear says running off to his room to retrieve the red necktie his uncle gave him last year.
 "Here it is, Mother Bear sewed it back together for me." Said Little Bear while tying it around his neck. 
 "Well now! I got a treat for you since you kept up with it for so long, go ask your mother if you can come play with me in the living room." Said Uncle Rusty with a slight lump in his throat. 
 "Mother Bear, can me and Uncle Rusty go play!" Little Bear said while tugging on Mother Bears dress. "I've got to go to the garden to get some vegetables for supper, sure go play, but don't get covered in mud like the last time you two played together!" Mother Bear said sternly not wanting muddy footprints tracked in.
 "Yes ma'am!" said Little Bear running back to his uncle who was still standing at the door. 
 "I take it your mother's gonna let us play." Said Rusty while pulling at his blue necktie.
 "Oh yes we can play, she's going to the garden to pick vegetables for later." Said Little Bear while opening the bottom half of the dutch door.
 "Ah, hows about we go into the living room, I got a special game I think you'd like!" Rusty said as Little Bear opened the door for him.
 "Oooo what kind of game, is it marble, jacks, card houses?!?" Little Bear said excitedly.
 "Nah, its much more fun than that, I'll show you if you'll lead me to the living room." Uncle Rusty said trying to hide the lump rising from his pants.
 "Right this way... Uncle what's that in your pocket, is it something to do with the game we're gonna play!" Little Bear said while walking into the living room.
 "Sure is, but you gotta be sure to not tell Mother or Father Bear about this, you gotta pinky promise me" Rusty said with his voice nervously gittering.
 "Of course, I'm a big bear now, I'm not scared of anything!" Little Bear reasurred his uncle while pinky promising him.
 "Ok then, close your eyes and I'll show you." Rusty said while taking a seat in a chair and pulling out his junk from his overalls. (see image 1)
 "Hehe, uncle whatever it is why do I need to close my eyes" Little Bear said giggleing at his uncles silliness, while his uncle unzipped his pants and pulling out his big uncut bear cock and balls.
 "Ok, you can open your eyes now..." Rusty said right before taking a deep breath.
 Little Bear opens his eyes to the big surprise of a large uncut bear pp and big heavy balls right in front of him.
"Uncle!, hehehe I never seen another bear's peepee before, what's that big of skin coming off the end??" Little Bear said intrigued, exited, and very curious about his uncle's grow up member.
"Ooh, uh, that's my foreskin, you can touch it if you want, try pulling it back." His uncle said with his large twitching erection in full view of his nephew.
"Interesting, veerrry interesting, Uncle look my peepee is getting bigger like yours!" Little Bear exclaims while reaching for his uncles long foreskin.
"And what a cute penis you have, pretty large for a cub your age~!" Rusty said in anticipation of his nephew's hand reaching for his member.
Little Bear runs his fingers along the drooping bit of skin hanging off his uncles now fully erect penis. His uncle shudders as he feels his nephew move his sensitive foreskin around. Little Bear pulls it back revealing his shiny pink glans. (see image 2)
"Just like that, pull it back!" Rusty said while watching his glans be in full view of the bear cub.
"Interesting, your peepee is looks just like mine now, just alot bigger." Said Little Bear
"You know, we can rub our peepees together if you want, it feels really good!" Rusty said while positioning himself lower in the chair.
"hehehe Uncle your so silly, that does sound fun. What do I do just touch yours on mine." Little Bear said while pulling his short chair over.
"Just rub ours together, you can even pull my foreskin over yours." Rusty said as little bear started playing with both of their penises, Rusty leaking precum all over Little Bears now fully erect penis. (see image 3)
"Oohhh uncle this does feel good, it kinda tickles when the pink part of mine rubs against yours, and that clear stuff coming out of yours makes it really slippery!" Little Bear said in full exitement of the new game his uncle has showed him.
They play with each others willies for some time when Uncle Rusty tells Little Bear to stop for a second.
"Alright kiddo, hold up a second, I got a idea. Hows about you try sucking on it, see how it tastes." Rusty said getting that excitly nervous lump in his throat again.
"Uncle but isn't that where you pee from?" Little Bear said confused about his request
"Yes, but there is also something else that comes from our peepees, I can show you but you'll have to work for it." Rusty said while pulling his foreskin all the way back and winking at Little Bear.
"Interesting... Ok I just have to suck on like a popscciiicle." Said Little Bear as he put his uncles tip in his mouth.
"Ohhhh! Exactly like a popscile, run your tounge around it if you want!." Rusty said already feeling tension building up in his balls.
Little Bear runs his tounge around his uncles glans and foreskin, sending him quickly to start cumming as his tounge reaches the underside of his penis
"Ohhh OHhhhh, ahhh here it comes little Bear!!!" Rusty says grunting while spurting ropes of cum all over his nephes face and onto the floor. (see image 5)
"Ewwww, hehe, uncle what is this sticky white stuff, its all salty and gooy." Said Little bear after getting some of his uncles spunk in his mouth.
"Wew I needed that... that's cum, its what babies are made with. I think you're old enough to cum now Little Bear." His uncle said out of breath and blushing deep red.
"Very, very interesting, so that's how babies are made, Mother Bear told me it was from the stork, I knew something seemed didn't seem right, I don't remember ever being in a storks basket." Little Bear said exitetly to see how it feels to do what his uncle just did.
"Can you make me do that Uncle Rusty, I want to shoot that stuff out of my peepee too!" Said Little Bear standing up and pointing to his penis.
"We can surly try now can't we, I think you're old enough, come here sit on my lap, I'll make sure you have a great first time!, but let me see that cute butt of yours first" Said Rusty while patting his lap, still fully erect and ready to go
"My butt, hehe, ok, Father Bear says I have a cute butt too, he said my balls and butthole is perfect." Little Bear said showing his butt to his uncle. (see image 6)
"Your father is certainly right, its very much pefect, now come here and sit that butt of yours on my lap, I'll make you squirt lots of that white stuff!." Rusty said beckoning the cub to come sit on his lap.
Little Bear comes to Uncle Rusty and right before he sits on his leg his uncle tells him to sit on the middle of his lap.
"Hehe uncle, but your pee pees in the way, I can't sit on it." Little bear said giggling, thinking his uncle was being silly again.
"What do you think I wanted to see your butt, press your butthole on my peepee, just go slow so you don't hurt yourself, ok!" Rusty said while gently pulling the cubs hips and butt towards his erection
"Hehheeh, Uncle Rusty, that feels weird, your poking my butthole with your peepee, is it supposed to go inside my butt?" Little Bear said trying to contain his giggles.
"Exactly, just one more good push and it should be in." Rusty said feeling his tip slip inside the cubs rear
Little Bear pressed harder on his uncles member, sending half the shaft inside him. Little Bear lets out a pleasured gasp as he's being stuffed from behind by a big uncut cock.
"Oh sweet potatoe pie, I didn't think you'd take it that easily, wooo boy you're stretchy!" Rusty said as waves of pleasure washed over him at the thought of him being inside his nephews butt.
"I put things in my butt all the time, mother bear has these toys that looks like your pee pee uncle rusty, I've put those in there plenty of times!" Little bear said with confidence to his uncle
"hhahahaha just like your old uncle Rusty, I'm no stranger to putting things up there myself, but if you're ready, hop on up here and lemme show you the real thing!." Rusty said picking little bear up around the legs and lifting him up onto his lap. (see image 7)
"Uncle!! Its slipping all the way in, ahhh its pressing against something inside me that feels really good!." Little Bear exclaimed as his prostate was getting pressed against.
"Told ya you'd love it, now let me hump you a bit and see how that feels." Rusty said as he starts moving his member deeper inside Little Bear.
"Ohhh uncle this feels amazing, my peepee is twitching every time you do that." Little bear said, feeling as his uncles uncut cock glides up and down inside of him.
"Try rolling your foreskin over the pink part, that'll really get you going, just tell me when you feel like ya gotta pee, I'll sit you all the way down then." Said Uncle Rusty, getting himself in position for what he feels is quickly to come.
"Oooooo Uncle Rusty, my butt feels so full and I'm feeling all tingly, am I about to shoot that white stuff like you!" Little bear said trying to catch his breath.
"Sounds like it-t, Ohhh good lord!" Rusty is cut off by the cubs intensely pleasured moans and butthole clenching rythmically around his member, sending him quickly to orgasm as well as increasing the intensity of Little Bears. The two both cum in sync, Little bear involuntarily pulling his foreskin all the way back as small ropes of cum land back on his penis, butthole clenching around Rusty's cumming cock each time he does. 
Soon after the who are left in a heavy breathing, gasping afterglow. Little Bear still sitting on his uncles cock, breathing heavily says to his Uncle. "I want to be inside you next time... that was super fun!!!". His uncles cheecks turn deep red and he averts his eyes. "I would like that very much, just ehhh help me clean this mess up before your mother gets back." Rusty lifts Little Bear off his half maste cock,(bonus starts here) butt covered in cum the two rush off the the bathroom to get cleaned up before dinner. FIN :D
(Spelling errors have to be overlooked, im writing this at 1:00am)
(There would be more images to go with the story, but the ai refused to give me anything worth using :( 

Bonus: Little bear still not satisfied, he sits on the couch and starts moving his foreskin up and down his still erect cock, quickly feeling the same tension in his rear that he felt while he was sitting on uncle rusty's cock. Uncle Rusty tells him to slow down be the cub doesn't listen, moments later Rusty notices his butthole rythmically contracting right before large ropes of cum start shooting out of the cub's penis. Holding his cock he spurts all over himself, until eventually he stops and is left panting from having came twice in just a few minutes. "Daaang cub, you're a bigger spurter than me, but uhh we really need to get cleaned up before you know who comes back. No sooner as he says that, Mother Bear comes back through the front door, in complete "shock" to see her cub covered in cum, and his uncle standing there, half erect penis out in front of him. She gets a naughty grin on her face as she starts unbuttoning her dress. "You're not slick, I've been watching you two since you started, I haven't came that hard in years, now come here you big burly man"... |Redacted|