What's up? I made this story because I live for these Sonic being bred by Shadow fics I've seen all over the internet. So I decided to make one because why not? Hope you enjoy!

What was once a heated rivalry between the two became instead a realized lust, as Sonic accidentally revealed his 'secret' anatomy to the black hedgehog.

It began with a familiar situation of a unwanted presence.

Sonic clawed at the tree behind him as he raced to finish himself off before there a chance of catching unwanted attention from others.

The blue hedgehog bit his lip suppressing his moans as he rubbed himself nearly raw at his clit, "C-Come on, almost there!"

Sonic had been struggling with his heat for several days, as it was his third mating cycle since it began he still found it difficult to fight this biological need.

He had a close call yesterday with Knuckles during one of their sparring sessions, with the logic that a little friendly combat would help to at least distract him from the burning urge within him.

However all it did was make the blue hedgehog become more frustrated as he took in the echidna's muscular form and musky male scent, to the point where after managing to knock the echidna down towards the ground found himself straddling his friend's waist, with his hips begging to rub them against the echidna's.

A stray thought of allowing Knuckles to plow him into the dirt made the hedgehog scamper off into the forest leaving behind a deeply confused echidna.

His brain nagged him that he needed to find a mate and as if to punish the hedgehog for not choosing to rut the echidna, made his heat even more intense than usual.

Sonic's tongue lolled out as he quickly approaching his climax, "A-Almost there!"

All that flooded his consciousness was the thought of letting Knuckles fill him up with his echidna seed and baring his children, pushing the hedgehog over the edge as he cried out in sheer pleasure.

He quickly covered his mouth to prevent further outburst and after giving himself a moment to recover from the peak of his orgasm finally breathed a sigh of relief as his heat was mostly abated at least momentarily.

But Sonic knew that his heat will return with a vengeance and at the risk of violating some poor Mobian who happened to come his way decided the safest location would be a small hut that he constructed for himself to spare his friend and housemate Tails from the onslaught of a frustrated hedgehog.

The blue hedgehog would've arrived earlier to pleasure himself inside the hut, but instead his body had other plans and essentially forced himself to satisfy his urge as running only made the sensation in between his legs agonizing.

Sonic opened the door to his hut, "This is stupid, how does anyone deal with this? This is driving me insane!"

He couldn't ask Amy since the pink hedgehog has yet to have her mating cycle yet, and out of embarrassment over his own anatomy couldn't ask Rouge or Blaze for advice.

Sonic groaned in annoyance as that unwelcomed burning returned so quickly, "I can't do anything about it! Why don't you just go away!"

Being in heat essentially stopped Sonic from being what he normally was, a hedgehog free to roam Mobius as a renowned hero and friend. If Dr. Eggman were to attack, Sonic knew his abilities would be severely limited as his body would be too focused on achieving its reproductive goals to work with any ally.

Suddenly there was a knock on the door, shocking the hedgehog, "Shit! Someone found me! Please don't be Tails..."

Deep down there was a part of the hedgehog that wished it was Knuckles so that the echidna could bend him over right there and fuck him senseless.

But instead there was someone he really did not want to see.

"Shadow?"

The black hedgehog in question raised an eyebrow, "Sonic? You live here now?"

Sonic frowned, "It's none of your business, what are you doing here anyways?"

"I was on a walk here, then I heard someone yell and it sounded a lot like you. I suspected you may have encountered one of Dr. Robotnik's inventions and was having trouble dealing with it." Shadow explained.

Sonic scoffed, "I can take care of any of Egghead's stupid robots, thank you very much."

Shadow crossed his arms, "I see, since nothing seems to be wrong I'll just...wait."

Sonic saw Shadow began to sniff the air, "What...is that?"

Quickly the blue hedgehog realized that the scent that drew Shadow's attention was his pheromones in the air, "I-It's nothing, you can leave now!"

"Is that...a female in heat?"

Sonic pushed Shadow away from the door, "You're just imagining things!"

Shadow's hedgehog side of his biology screamed at him at the possibility of a needy female in the area, "No, I can definitely smell it. Are you...sleeping with someone in there?"

"Uh...y-yeah! I'm totally scoring in here right now and I would appreciate if you gave us some privacy." Sonic implored hoping Shadow would accept his bluff.

Shadow smirked, "You know, I haven't had any...relief in a while, perhaps I can get some help from her as well."

"Hey wait-"

Sonic was pushed aside by Shadow, "...don't come in."

Shadow looked around in confusion, "Where is she?"

Sonic sighed, "There's no one here Shadow."

The black hedgehog turned to the other, "Then where is that smell coming from?"

Sonic looked away, "You don't want to know."

"Just tell me, I don't like being tricked into thinking there's someone in need of a good fuck!" Shadow demanded.

"It's me." Sonic simply answered.

Shadow frowned, "You? But you're-"

"A dude, I know, but there's something different about me."

Sonic turned around and bent over to reveal himself to Shadow, "You see that?"

The black hedgehog's mouth gapped open in shock, "You're...female?"

Sonic shook his head, "Not exactly, I'm a guy, just with lady parts for lack of a better term."

Shadow took a while to process this information, "I...didn't even know that was possible."

"Read up on it Shads, it's very rare but it still happens." Sonic said sitting down on the hammock.

"I uh...don't know what to say." Shadow awkwardly said.

Sonic huffed, "Not anything really, so anyways...do you want to fuck me or not?"

Shadow was taken aback by his sudden question, "What?"

"You came barging into my hut and you're getting blue balls because you thought there was a lovely lady here, so I'm asking you right now if you want to fuck me until we're both satisfied?"

Shadow knew that Sonic was a direct kind of guy, but not that direct, "Do you want it that bad?"

Sonic groaned, "Are you gonna slide it inside me, because my pussy is burning for a dick and yours is the only one here!"

Shadow sighed, "I've never seen you this aggravated before."

"Dude, my body's literally telling me to have babies with you, now I can't guarantee that such a thing won't happen, but right now I'm literally a few seconds away from shutting the door and humping you dry." Sonic stated as the last of his sanity slipped.

The smell of Sonic's pheromones combined with his pre-existing condition of not getting off for a measurable time finally got to the black hedgehog.

"Alright, I'll do it, but under my terms." Shadow answered.

Sonic smiled, "Took you long enough to get around to it, now, what do you want from me?"

Shadow seemed both intrigued but also a little apprehensive at Sonic's question, "What do you mean?"

The blue hedgehog rolled his eyes and walked up to him, "You know...do you need help getting it up?"

Shadow felt Sonic's hand begin rubbing at his crotch, "I-I don't need help."

Sonic grinned, "You clearly do, luckily I'm one to please."

Without warning Sonic pressed his lips against Shadow's, at first the black hedgehog was surprised at his counterpart's sudden action but quickly accepted it.

Any of Sonic's previous bravado was soon swept away, leaving behind a very horny hedgehog.

Sonic felt Shadow's member quickly begin to harden, "That's it, now we're getting somewhere."

Shadow wanted to already get to the part where he was railing Sonic against the wall, but he figured a little foreplay would ease any tension between them.

"Have you done this before?" Shadow asked.

Sonic shrugged, "I watched a lot of porn, and I did practice with some toys, but not the real thing. And this thing right here...oh mama."

The black hedgehog's member was nearly fully erect, and Sonic looked at it with both anticipation and some concern on whether his anatomy could fit it or not.

Shadow groaned as Sonic's hand glided up and down his erection, "You definitely seem to know what you're doing."

Sonic chuckled, "I hope so, otherwise I might put you in the hospital."

"I'm the Ultimate Lifeform, I'm not worried about your...lack of experience." Shadow said trying to hold back his groans.

Sonic licked his lips, "Well, maybe you have the Ultimate cock, looks so good that I just have to have a taste."

The blue hedgehog fell to his knees feeling his pussy dripping as his entire mind fell to the whims of the whirlwind of hormones inside him.

Sonic kissed the tip of Shadow's length, "It looks even bigger down here..."

Shadow smirked, "Think you can handle it?"

"We're about to find out."

At first Shadow was concerned on whether Sonic could even open his mouth wide enough to properly service him, but the blue hedgehog was able slide the first few inches into his mouth fine enough.

The scent of Shadow's own pheromones emitting from his crotch drove Sonic into new depths of horniness, as his brain seemingly switched to pleasing the male by any means possible.

Sonic attempted to force more of Shadow into his mouth, but upon reaching the halfway mark stop as he felt his gag reflex about to be activated.

The black hedgehog couldn't help but chuckle slightly at the sight of Sonic struggling with his cock, "What's the matter, met your match?"

Even under his spell the competitive side of Sonic was evoked by Shadow's taunt, "I'll show you!"

Shadow grunted as the blue hedgehog began bobbing back and forth along his length, "D-Damn!"

Sonic wanted Shadow's cock in him so badly, but at the same time he wasn't going to let his rival belittle his abilities.

"Slow down there!"

Shadow's request went unheeded however as his blue counterpart both fueled by arousal and competitiveness was fully engorged in his mission to suck the life of the Ultimate Lifeform.

Lewd slurping and moaning noises filled the hut as Sonic relished in the act of giving head to his rival.

"H-How are you so good at this?" Shadow asked gripping onto the wall behind him.

Sonic looked up at the black hedgehog with a dopey grin on his face, "My dude, I mainline chili dogs for a living, not trying to sound crazy but your dick is shaped a lot like one. Maybe an Jumbo XL one though."

Shadow huffed at his own cock being compared by a chili dog, but he knew that the blue hedgehog's diet was essentially just that.

"I would appreciate you not making those kind of comparisons."

Sonic chuckled, "I get it, comparing you to a food isn't the best thing for the mood, but what I will say is that you're looking like a tasty snack."

Shadow groaned as the blue hedgehog returned to his cock, "I would say t-the same for that pussy of yours."

Sonic's tongue swirled around the head of his rival's erection as he rubbed at his clit in anticipation for whatever Shadow had planned for him.

"Well luckily for you, this pussy's all yours today since you happened to waltz right into my domain."

Shadow tensed up as he felt his orgasm quickly approaching, "Damn it, I'm getting close..."

As soon as the blue hedgehog heard that he immediately stopped to Shadow's anger, "Why the hell did you stop?"

Sonic massaged Shadow's sack, "How long has it been since you got off at all?"

"I've...lost track, maybe a week?"

"I figured that, you got some nice fat balls in here man, I just didn't want you to tap out after busting just once."

Shadow smirked, "There's no need to worry that, I can-"

Sonic promptly returned to sucking Shadow off, catching him off guard.

"N-Nnh, fuck!"

After teetering on the edge for a teasing moment the black hedgehog could no longer suppress himself and soon jets of his seed coated the inside of Sonic's mouth.

The blue hedgehog aggressively rubbing his lower lips moaned as he could feel and taste each shot of hedgehog fluids.

Shadow's body loosened up as the last of his first orgasm of the day exited him, "F...Fuck, sweet Chaos."

Sonic greedily gulped up the warm load, "Definitely got a nutty flavor."

After giving his rival's cock one last kiss he got up and walked to the other side of the hut, "Hey Shadow."

The black hedgehog saw Sonic bend over to reveal his dripping pussy, "Don't be shy."

Shadow wasted no time and walked right up to his rival, pressing his body firmly against Sonic's, "You're driving me crazy right now."

Sonic smiled, "Even more than usual?"

Shadow rubbed his hard-on against Sonic, "Maybe, but this time...I can fix that."

Sonic's tail waved as the hedgehog panted, "Stop being a tease and fuck me already then!"

Shadow bit the blue hedgehog's ear, "Buckle up."

Both groaned in pleasure as Shadow shoved himself inside Sonic and immediately began thrusting as he felt just how hot and wet Sonic's pussy was.

"You like that?"

Sonic nodded as the one thing his body has been desperately craving for several days now, "Yes! Now stop talking and start fucking!"

Shadow wrapped his left arm around Sonic's chest, "I don't need to be told that!"

Both hedgehogs vocalized lewd noises as Shadow claimed Sonic as his, "Yeah, that's it, take my cock."

Sonic bit his lip as he felt the black hedgehog's thickness penetrate deep into him, "I-It's so big, unh!"

Shadow has been with many women before, however there was something about Sonic having a pussy that drove him deeper into lust than before. Maybe it was the thought that he was fucking his own rival who was begging for more of his dick, or maybe it was the fact that it was another hedgehog who was in heat.

Either way, Shadow was more than happy to take Sonic as his mate.

Shadow pulled out of Sonic and spun the blue hedgehog around, "Who knew all this time you just needed a good dicking?"

Sonic huffed as Shadow raised his legs, "You gonna gloat or are you going to fuck me?"

Shadow smirked, "I'm not done yet."

The black hedgehog promptly reentered his rival and resumed his aggressive thrusting, this time forcing his tongue into Sonic's mouth as the blue hedgehog loudly moaned into his.

"Fuck, you're so hot and wet right now, I can tell your body really wants me to knock it up." Shadow growled.

Sonic shuddered as Shadow slowly pushed his cock right up to his hilt, "S-Shadow!"

"You want my child don't you? This is why you're letting me fuck you right?" Shadow questioned his rival.

"So what if I do?" Sonic asked between gasps.

"If you really want one, you'll have to be my mate then." Shadow stated.

"Y-Your mate?"

Shadow licked up Sonic's neck, "If you want this cock, you'll say that you belong to me, that only I can fuck you, that I can breed you."

Sonic found himself at the edge of his climax already, "I-I..."

"Say it! Right now!" Shadow growled.

"I want it, I want you! Give me your kids!" Sonic cried out.

Shadow grinned, "Good."

Shadow smashed his lips into Sonic as he plowed himself into his now mate.

"S-Shadow, I'm getting close!" Sonic cried out between kisses.

"That's it, cum for me Sonic, I want to hear you yell!"

The black hedgehog accelerated to full speed in his thrusts, driving Sonic to his orgasm.

"Shadow!"

Sonic wrapped his legs and arms around the black hedgehog as his entire body reverbed due to the intensity of the orgasm that he was experiencing.

Shadow grunted as he felt his cock being squeezed, "Damn Sonic, you want my cum that bad? Well I'll give it to you!"

Sonic cried out as he felt Shadow crammed every inch of him inside, "W-Wait!"

Shadow gritted his teeth, "Fuck!"

The black hedgehog doused the innards of his rival with his thick virile seed as he experienced the first sex-induced orgasm in a long time.

Sonic could feel each shot of Shadow's cum enter inside his womb, and the blue hedgehog momentarily blanked out as his already existing orgasm reached new heights.

Shadow laughed as the last of his load exited him, "Haha, fuck, good boy."

Shadow and Sonic more sloppy kisses as the black hedgehog kept his cock inside his blue counterpart's now warm, sticky tunnel.

"H-Holy crap, that was awesome." Sonic gasped.

Shadow licked his lips as he already began resuming his thrusts, "Luckily for us, I still have plenty of energy left. This is going to be a long night."

Sonic shakily smiled, "Fuck yeah, give more of that."

Throughout the rest of the evening, Shadow ended up injecting several more loads into both Sonic's mouth and pussy as he tested new positions for his and his rival's pleasure.

By the time dusk arrived, Sonic laid on the floor completely in bliss as Shadow's cum poured out of his heavily used hole.

Shadow stood triumphantly over his exhausted yet satisfied mate, "I have to say I like this little hut of yours, it's perfect for me to use you as a fuck toy whenever I want."

"A-Anytime you want Shads..."

Shadow chuckled and rubbed Sonic's belly, "I can't wait to see how many children you'll carry."