Chapter 8: Time Will Tell

“You sure about this?” Tails asked.

“Absolutely, little buddy. I can't wait to see what we have to look forward to when you're older.”

“Ok then.” Tails pushed the needle into his arm, injecting the serum into his bloodstream. Laying back on his bed, Sonic smiled and left the room. 
A few weeks ago Tails had created a special serum containing nanobots which could temporarily replicate another living thing's age. Last time he used it on Sonic, regressing his body to being a preteen like Tails. It was so much fun being intimate with his partner being on more equal footing. However, now it was Tails’ turn. A slight modification to his original serum, and now he was ready to grow up for a brief time. 

Taking off his shoes, gloves, and socks, the young fox laid naked on his bed awaiting the change. He closed his eyes and relaxed. Per Sonic's recounting of the experience Tails knew it wouldn't take long. After a minute, he felt a strange tingling sensation throughout his whole body, accompanied by a little pressure. It wasn’t painful, but it was strangely uncomfortable. As the transformation slowly took hold, he could feel a warmth in his loins. It was similar to arousal but he could tell he wasn't hard. 

After 5 minutes the strangeness  faded and Tails was left feeling normal again. Opening his eyes he got the first glimpse of his teenage body. His toes and fingers were pointed now, more like claws. His Golden fur was thicker and fluffier too. The fur was especially more ample on his chest and around his boyhood. Sitting up his twin tails curled around him. They too were loner and fluffier. Hugging them to his chest he smiled at the comfort they brought him. 
As Tails caressed his fur, Sonic wandered back in the room as he heard stirring. Stopping in the doorway, Sonic froze, stunned. Tails was so HOT! He was much taller now, possibly even taller than Sonic. His fluffy twin tails curled around his body drawing Sonic's gaze into the fox's chest and lower. A thick nest of pubic fur hid Tails’ package, letting him appreciate every curve of his body. 

“Sonic?” Tails asked, jumping to his feet upon seeing his stunned partner. “What's wrong?”

“I…the…uh…” Sonic couldn’t even form words. Without even realizing it his member poked out, hardening in front of Tails. 

Glancing down at him, Tails smiled realizing what was happening. He giggled and walked over to him. 
“I must be pretty sexy to get you turned on tha fast.”

“That's an understatement!” Snapping out of his trance, Sonic's face lit up. “Damn Tails!” Sonic stepped face to face with him, seeing he was indeed now just slightly taller. Without hesitation he pulled off his gloves and ran his fingers through Tails’ fluffy chest fur. As he explored the fox's older body, the tip of Sonic's shaft gently grazed Tails’ pubic fur. 

“Mmmm, that feels nice,” Tails hummed. Placing both hands on Sonic's shoulders he pushed him down a bit further. 
“Go a little lower Sonic,” Tails said. He was eager to see how his body had grown further, and felt a strange sense of empowerment now being bigger than Sonic. Pushing the blue hedgehog onto his knees, Tails held his head with both hands, gently massaging his quills. 

Sonic wasn't even phased by the sudden and more dominant way Tails was treating him. Besides, it wasn't the first time his partner took the lead. He in many ways enjoyed it actually. Letting his fingers trail from Tails chest, down his hips, and across to his thighs, Sonic was surprised Tails’ boyhood still wasn't poking out. Pushing his fingers up into the tuft of pubic fur, Sonic quickly found the fox’s balls. Unlike the tight barely hanging package he was used to, the fox's teen body now had big swollen balls. They were barely being contained by the mass of pubic fur, which as Sonic parted they slumped out into the open air. Gasping under his breath, Sonic cupped one hand under them, feeling their weight. 

Under Sonic's touch Tails could now more readily feel his new body. The gentle touch on his sack sent shivers through his body as he realized how big he'd gotten. His balls were also more sensitive now. They felt so incredibly full. Perhaps this was from the accelerated aging. All the extra years meant a lot of build-up all at once. Biting his lower lip, Tails continued to message Sonic's quills and ears as he felt the hedgehog's hands approach his sheath. As his thick fur was parted away, Tails’ tip poked out. 
“Oh man,” Sonic whispered. Just seeing Tails’ matured tip caused the hedgehog's own boyhood to twitch. He could tell just from the tiny bit already exposed, Tails was MUCH bigger than before. Rubbing the tip between his thumb and fingers, Tails' cock quickly pushed out, getting rock hard in Sonic’s grasp. 
“No way!” Sonic gasped, “Tails you're fucking huge!” Immediately Sonic released his grasp,  stood up, and stepping back gave Tails a chance to see himself. 

Looking down at his throbbing member, Tails’ jaw dropped in amazement. Sonic wasn't kidding. His former 4 inches now rivaled Sonic's at nearly 8. Unlike the hedgehog's boyhood though, Tails was also considerably thick! His pulsing knot was also already exposed. Without even touching himself, his monstrous vulpine cock was eagerly leaking streams of precum onto the floor. Slowly he reached down and grabbed his lower shaft with his right hand and cupped his heavy balls with his left. Just a light tug and he felt himself getting lost in the incredible pleasure. It was like all of his normally high levels of pleasure and arousal were dialed up to eleven. Turning to Sonic, who been staring at him smiling, Tails shocked face turned to a devious grin. Leaping at him, Tails pinned Sonic to the wall by his wrists and pressed their lips together. 
Sonic gasped as Tails slipped his tongue into his mouth. The fox's tongue was wider and more flat, high he used to wrestling with Sonic's. Sonic winced as Tails took control. His own dick pressing against the he golden fox's chest, and the twin tails wrapped around his back. 

“Mmmmmmh hmmmmm Mmmmmmh, Mwah!” 

Sonic gasped already slightly out of breath. Tails growled, his animal instincts taking over his more regularly timid demeanor. Sonic couldn’t believe how aggressive Tails was being. As frightening as it should have been, he was willfully submissive and immensely turned on. 
“T…Tails?” He asked, letting out a slight whimper.

“Bed. NOW.” Tails grunted, throwing Sonic from the wall, across the room. And onto the bed. Leaping through the air, Tails straddled Sonic, keeping his arms pinned down. Their dicks rubbed together as Tails leaned down and licked Sonic's chest and up his neck. Gently humping against Sonic’s cock, Tails’ own impressive boyhood throbbed,  coating Sonic with it's precum. 
Tails couldn't control himself now. His body just moved on it's own. Maybe it was a side effect of the serum, or maybe his matured body was so riddled with the influx of testosterone that his libedo was out of control. Whatever the reason the young fox wasn't going to be his normal self for the night. He was bigger, hornier, and ready to claim the blue hedgehog's body. This wasn't just about their relationship. Tails had become an alpha and was marking his territory. As he licked across Sonic's body, occasionally going back for a quick kiss, Tails grew more and more aroused. Now practically shooting his precum out, he knew it was time to claim his lover. 
“Roll over,” Tails grunted.

“Huh?” Sonic mumbled in a daze. 

“Roll!” Tails let go of one wrist and flipped Sonic onto his chest. 

“Oof…uh…he Tails? Aren't you being a little rough with m…MEEEE!” Sonic shouted as he felt Tails tongue slip inside his tailhole. “Oh…fuaaaaa…yeaaaah.” Sonic knees shook as Tails invaded his body. His hedgehog cock throbbed feeling the fox's tongue lap against his prostate. That was certainly something Tails couldn't do before. After a minute of deep rimming, Tails pulled his tongue out and readied his tip at Sonic's puckering entrance. 

“You're ass is mine Sonic,” Tails growled, “Don't ever forget it!” Not giving the already submissive hedgehog a chance to respond, Tails thrust forward, spreading Sonic wide as the first half of his cock slid inside.

“AAAAH!” Sonic let out a short scream. He was so used to Tails having a cute little dick, that he was immediately surprised by how quickly Tails penetrated him. He expected to struggle with the considerable girth of the fox's older body, but thanks to the tongue work and ample precum there was little resistance. His tailhole stretched wide as if he was already accustomed to it. The pleasure was unheard-of too! Despite knowing Tails wasn't even all the way inside him, he still felt ready to cum. He felt so full already but he still wanted more. He wanted all of Tails…he needed it.
“M…more,” he whined. 

“What's that my little hedgehog?”

Oh fuck. Tails was now calling him little. Why was he so turned on by that. 
“Do it, Tails! Fuck me with that big cock!” Sonic screamed, he couldn't help but beg for it now. 

“Hehe, that's a good boy.” Tails chuckled. Grabbing Sonic’s hips firmly, Tails plunged his remaining length deep into the blue hedgehog's body. His knot bumping against Sonic's tail, both boy let out a long primal groan. The tightness of Sonic's tailhole and the pressure of Tails’ cock instantly pushed both boys into their first orgasm for the night.
Sonic's cock throbbed wildly spraying the bed with nearly a dozen blasts of hot cum. Meanwhile, Tails unleashed ropes of thick love juices deep inside the blue hedgehog. It didn't take much, before his cum was leaking out around Tails cock. With his nearly 8 inches taking up Sonic's insides, there wasn't anywhere for the fox's ample load to go. 

As their climaxes tapered down, Tails was still wanting more. Readjusting his grip on the blue hedgehog, he began thrusting in and out of his tailhole. 
“Huh, wait. Tails, I just…ah, ah ah, what are you d…”

“I told you Sonic..” Tails growled, gritting his teeth, “You. Are. MINE!” 

Sonic's eyes shot open wide. Having already climaxed, his normal lust had dissipated and he was thinking more clearly. Gulping, he now understood just how Tails was treating him. Dealing with the rush of hormones all at once from the rapid aging, might have turned a darker switch in his little buddy's subconscious. 
“Hey uh, Tails? Can we…oof… talk about…ah…this? I…ah…I just came.” Instead of acknowledging Sonic, Tails just grunted and began thrusting harder. Sonic was actually a little afraid now. Tails wasn't treating him like a lover, but instead like a toy. Gulping again, he shivered. Despite his protest, he felt himself getting hard again and the pleasure started to take over his doubts. 

PLAP PLAP PLAP PLAP PLAP PLAP PLAP 

“Ok, whatever.” Sonic thought. No sense fighting him over NOT having sex. Besides, he was still enjoying having his tailhole destroyed. 

PLAP PLAP PLAP PLAP PLAP PLAP PLAP 

Sonic moaned loudly as he felt another round getting milked out of him. His 8 inch cock twitched sending another few streams of cum onto the sheets. Tails wasn't even phased by this. He just kept mercilessly pounding the teen's tailhole. 
“F…uuuck, Tails. Please…I…I can't…” Barely able to hold himself up on his elbows Sonic was now exhausted. His body was still pumped full of Tails’ cum and precum, and the fox wasn't slowing down. 

“We're done when I say so!” Tails barked back. “You’re gonna take my knot!” Tails growled and pushed hard against Sonic’s tailhole. 

“No Stop, you're too b…” POP “AAARGH, TAILS!” Forcing his thick, swollen knot into Sonic's body, the hedgehog felt a third and one of the most powerful orgasms he ever felt ravage him. He didn't have any cum left, but that didn't stop his cock from throbbing as if he could still shoot. 
“Oh, man,” Sonic moaned. He was now completely resigned to Tails dark lust. Feeling every last bit of resistance melt into the sheets, his mind went blank as the fox blasted another huge load of cum into his body. He felt his stomach bulge out to accommodate the thick love juices of his partner. 

Grunting and moaning, Tails finally was spent and he collapsed on Sonic's back. The second he fell onto the bed, he was out cold. Slipping into a deep sleep while his cock was still knotted inside the blue hedgehog. 
“Holy fuck Tails, that was…Tails?”
Tails let out a long snore, and involuntarily he curled up hugging Sonic from behind. 
“You're kidding, right?” Sonic chuckled. Let out a sigh of relief, he at least knew it was over. He couldn't believe how aggressive Tails was. He was glad the sudden alpha-Tails was just a one night animal, otherwise he'd probably never walk again. Despite his earlier protests, he was actually glad to have experienced being bred like that. A sense of deep gratitude also filled his mind, realizing he'd have several gradual years before his little buddy was that big again. He'd have plenty of time to grow into the change. Still though, it felt pretty amazing to have a massive cock knotted inside him. It was going to be hard to go back to taking the young fox's 4 inches again. Letting himself rest, he smiled as his dick slipped back into his slit and he joined Tails in dreamland.

… …

“Ack, Sonic wake up!” 

“Wha!?” Sonic sat up in an instant hearing the frantic distress in Tails' voice. Tails threw his arms around him and began sobbing. “Tails?”

“Oh thank Mobius you're not dead, I was so worried!”

“Why would I be dead?” What's going on?” Sonic looked around the room trying to get his bearings. Just as he was last night, the two of them were on Tails’ bed, sitting near the center which was still damp with cum. 

“I'm so sorry, Sonic. I completely lost myself last night. I was just so horny and I couldn't stop. I remember you telling me, but I didn't listen. Please don't hate me!” 

“Whoa, whoa, is that what this is about?” Sonic pulled him away and held him by his shoulders. The serum had worn off overnight and Tails was back to his old little self again. Smiling, Sonic wiped the tears from the young fox, and kissed his forehead. 
“Tails you know I'd never hate you. While I'll admit you were pretty aggressive, I still had fun.” 

“Sniff. You did?” Tails’ sorrow broke into a small smile as he sniffled. “I…I didn't break you?”

“Pfhaha, please. If Eggman's robots haven't hurt me by now, there's not much you can do. Although I don't think I'll be running anywhere today.”

“Pfft,” Tails began giggling. “So…you're not mad?” 

“Do I look mad?” Sonic replied, looking lovingly into his eyes. Raising his hands up to Tails’ cheeks, he gently kissed the young fox. “You're my sexy boyfriend Tails. I love you no matter what.”
Tails smiled wide and returned the kiss. The two spent the next few minutes making out, as Sonic consoled his little lover. 
“Mwah,” Breaking from him he smiled seeing Tails had calmed down. “Though you better believe I'm gonna pay you back next time we do it.” 

“Uh,” Tails giggled nervously. 

“And I won't be giving any notice either. So watch out. One of these days I'm gonna pin you down and breed you into next week.”