Chapter Text
Donatello had learned a lot in the last month at the farmhouse. For one, he learned that you couldn’t follow around the girl you liked like a sad little puppy and hope that one day she’d look your way. He was surprised to find he was okay with the two of them just being friends. He'd also learned he and Casey actually had a lot in common and maybe the wannabe vigilante wasn’t so bad after all. (Yes, shocking to him as well.) Oh, also Bigfoot was real, as well as dream beavers apparently?
He had almost made his peace with the absurdity that was his life… And then he got eaten by a mutated muscle car and any shred of self-confidence he might have had was gone. Over the last few days his doubly-mutated body had slowly been absorbed. Now to any innocent bystander he would look like a regular mid-life crisis mobile.
Until he could find a way to safely de-mutate himself into a mutant turtle and not a regular one, he’d be stuck like this, malformed and useless to his team. At least for now the mutation seemed stable again. But for how long?
Casey had hardly left his side since. Sure, they had grown closer during their time away from the city but he was still baffled that the boy suddenly wanted to spend so much time with him.
At the moment, Casey was leaning his head into the driver’s side doorway. “Can I try something stupid?”
Hm. He didn’t like where this was heading. “Be careful, Casey,” His voice crackled through the car’s speaker.
Casey laughed. “Careful is my middle name.”
“No it’s not, it’s-” Donnie’s words dried up in his mouth as Casey placed a hand on the seat and climbed inside.
“Huh. It’s kind of cozy in here,” Casey said as he settled into the driver’s seat. He ran a hand over where the center console should be and began feeling around for knobs and switches. To Donnie it felt like Casey had somehow found his way under his shell. The car shuddered.
Casey pulled his hand back. “Wait, can you feel that?”
“Um… Yeah?”
“Shit, I’m sorry dude, I wasn’t thinking. Do you want me to get out?”
“It’s fine.” Donnie sputtered weakly. In all honesty it was strange but not necessarily bad to have Casey sitting there inside of him. What a bizarre thought. “Would you just… warn me first?”
“Yeah man, of course. Sorry for just jumping in.” He looked around the interior – without using his hands this time. “It looks like everything’s intact in here if you ever wanted a driver.”
“What does it look like?”
“I dunno, meaty? It’s very pink in here.” Casey turned to look in the backseat. “Oh man, your guts are just chilling back there like big snakes. Are they supposed to move like that?”
“Peristalsis, probably. That’s normal.”
“If you say so.” Casey’s voice was unsure. “I’m not hurting you, right? I think I’m sitting on more of your guts.”
“I’m fine. You just startled me is all.” Donnie didn’t feel the need to mention that Casey’s body heat was strangely soothing, like a warm cup of tea.
“Alright,” Casey fidgeted with his hands. “Do you… Want to try it? Driving together, I mean.”
If questions could be catalysts this one certainly had his engine revving. “Yeah, let’s give it a shot.”
Casey hopped out to open the barn doors and Donnie was surprised to realize he missed his presence. Even more surprised to feel his body reaching for Casey’s when he returned to the front seat. He curled around his form – purely to keep him secure in lieu of a seatbelt of course. Maybe he was imagining it, but Casey seemed to lean into his touch.
“Alright big guy, let’s see what you can do.”
His wheels kicked up dust as he peeled out of the barn and down the dirt road. “Watch yourself, Jones. I can throw you out anytime I want.” At first, he wasn’t sure if the boy even heard him since he started whooping and hollering as soon as they were on the move. After a few moments Casey let out a giddy laugh and grabbed the steering wheel. “You wouldn’t!”
“Try me.”
“Just you wait, babe I’m gonna rock your world.”
Before Donnie could process his confusion over the pet name, Casey switched gears and floored the gas.
Casey was right. There was something about the way he drove, hugging every corner, reckless but precise. His hands gripped the wheel tighter as they drifted around another curve and Donnie felt himself begin to purr, the noise a mix of mechanical rumble and his own voice.
“Still good, Dee?” Casey asked, his voice low.
“Yeah, yeah. Keep going, please.” Donnie had been letting Casey take complete control, but he felt his anxiety trickling back in at the question. “I mean, if you still want to...”
“Fuck yeah, I do. I feel like David Hasselhoff in Knight Rider.”
“Half the time I don’t know what the hell you’re talking about.”
“It’s a good thing, trust me. Now let’s go, KITT!”
※※※
A while later Casey pulled over on the side of the road and leaned forward so his head was resting on the fleshy steering wheel.
“You okay?”
“Yeah, I just…Fuck.”
Donnie realized he was shaking. “Are you… Sure?” he asked tentatively when Casey still didn’t raise his head.
“I think there’s something wrong with me.”
A flash of panic. “You’re hurt? I can’t help you like this. Let’s get you back to the house so the guys can take a look at you.”
“No, not like that, Dee. I’m okay.” He rubbed a hand along the dashboard and Donnie stilled under his touch. “I just wish you had your body back, that’s all.”
“I don’t see what that has to do with anything.”
“Y’know, I never understood why people said muscle cars were sexy. I think I get it now though.”
Now he was properly confused. “Casey, what’re you talking about?”
“I’m sorry, I can’t think straight when I’m literally inside of you.” He finally lifted his head and leaned back into the seat with a sigh. “Never mind. Let’s just go back to the house.”
Donnie turned their conversation over and over in his mind like a new piece of Kraang tech as Casey drove them back to the farmhouse. He definitely felt something after that drive, but he didn’t know how to explain it. His organs were all in different places and warped beyond recognition which could be why it was so hard to understand what he was feeling.
On the other hand, he had certainly never felt like this about April.
※※※
Once the lights were out in the barn and everyone had settled back in the house, Donnie slept. There wasn’t much else he could do in his new vehicular body. This last week was probably the most well-rested he’d ever been.
He usually dreamed of New York, and the home and people they left behind. To his puzzlement, many of his dreams had also started featuring a certain dark-haired boy with a too-loud voice and easy smile.
Last night his mind had offered up the image of Casey sweating underneath him with a wrench in hand. Dark, viscous oil coated his fingers, dripping down past his elbow. His expression focused and intense.
He doesn't know what to make of this.
It felt different when the sun rose and Casey joined him again in the barn. The human was unendingly curious and seemed eager to figure out how to turn Donnie back to normal. Perhaps this should be unsurprising, given his affinity for bizarre horror films.
For Donnie’s part, he'd never been more interested in the boy… And their previous rivalry had bordered on obsession.
There was a discordant ache where flesh and metal combined and a strange sort of hunger he couldn’t explain. He was worried at first that the vestiges of Speed Demon wanted to devour Casey the same way he was once swallowed up… But now when Casey looked under his hood he just felt exposed and sensitive to the touch.
“You’ve got a basic V12 in here but your uh… guts have taken over a lot of real estate. Do you want me to try feeling around?”
“Sure,” he said quietly. The question made him flustered, but he didn’t know why. He was just a car. A weird fleshy car. Cars had mechanics just like people had doctors. No reason to get so riled up.
Casey wasted no time getting to work. He rolled up his sleeves and pushed flesh aside to try and see better before ultimately giving up and plunging an arm in a gap in soft tissue. “Not a lot of mechanical parts in here, Dee. Hey, you’ve still got a tank of wiper fluid though. Ha!”
“Like lacrimal ducts…” Donnie said distantly. Casey’s busy hands were too distracting.
God, that felt like... It felt obscene. The weird thing was, he didn’t want Casey to stop. He let himself get lost in the sensation, whimpering as Casey pushed further, twisting his fingers… then came crashing back to reality as he realized he had made that noise out loud.
“Shit. Sorry Dee, you okay?” Casey froze and began pulling his hand back.
No no no, please don’t stop now... He bit off a whine, just barely, and laughed nervously instead. “You’re good. It just uh… Tickles.”
Something shifted in Casey’s expression but he couldn’t place it. “Do you want me to stop?”
“… No? I mean. You can stop if you want to though.” Ugh, this was mortifying.
“Okay.” A slow smile crossed Casey’s lips. “Are you like… Getting off on this?”
Donnie really wished he had his shell back so he could crawl up in it and never come out again. “What? Um. No…? I uh…”
“It’s cool Donnie, I’m into it. You’re cute when you’re desperate.”
That’s it. He’d gone and lost it for real. Speed Demon must have eaten the useful parts of his brain and left him with whatever piece was making him melt at the heady sound of Casey’s backhanded praise. He tensed as the boy leaned towards him. “What’re you doing?”
“You said you didn’t want me to stop, right?” Casey bent under the hood again and trailed his fingers near where he had just been digging around. “So… Where do you want me?”
A million scenarios flashed through Donnie’s mind, none of them chaste. If he had his body back maybe he would know what to say in response, but like this…
“Whatever you were doing before was uh… Nice?” Donnie couldn’t help but laugh at the absurdity of it all. He was sure he sounded insane. That is, until Casey shifted his weight against his front bumper and Donnie realized he wasn’t alone in his arousal.
Wow, Casey Jones really was up for anything, huh? He should have known.
With his hand back inside, Casey resumed his earlier exploring, but this time his wiry fingers were gentle and deliberate. Teasing. “Talk to me here. I wanna make sure I’m hitting the right spot.”
“How am I supposed to know what’s—ngh.”
“Just like that babe, that’s all I need.” Casey pressed a kiss onto the exposed engine. “You still okay?”
“Yeah…”
“Good.”
“But... I can’t do anything for you when I’m like this. That’s not fair.”
“Don’t stress. We can worry about that later. Let me make you feel good. Please?”
Donnie wasn’t used to this much attention or giving over control of his body, but he tried to let go. He trusted Casey. Even if the human drove him nuts most of the time.
The problem with being a car now instead of a mutant humanoid turtle is that he couldn’t cover his mouth to try and hide the pathetic, needy noises currently bubbling out of him. He still tried though, diverting as much of his attention as he could to not moaning Casey’s name.
Unfortunately, Casey had taken notice. “Don’t stay quiet on my account.”
There was no way. No fucking way he would let himself moan right now. It was too embarrassing. He was already struggling to wrap his head around the current situation as well as the sudden desire to touch Casey, to hold him closer. What on earth was wrong with him.
“Cmon, Dee. No need to be shy. I want to hear you.”
“But… the others,” Donnie spoke slowly, as if he were gritting his teeth, but the only teeth he had were lining the front of the car. Sharp, pointed, and dangerously close to where Casey was standing.
“Barn door’s closed and locked, babe. C’mon. Let me hear you scream.”
“No!” he said indignantly. Okay, maybe he also wanted to throttle Casey. Just a little bit, for his own good.
Casey pulled out, putting both hands on the outside edge of him and leaning back. “Alright, I’ll stop if you’re not enjoying yourself.”
“Casey.” He tried to make his voice sound firm, commanding, but… Oh no. He had just moaned his name, hadn’t he? He could feel his insides spasming, protesting the sudden absence of Casey’s ministrations.
“Yes…?” Casey said sweetly.
Donnie suddenly did want to scream. In frustration. A threatening rumble started in his core as Casey sat there waiting with a shit-eating grin on his face. “Keep going,” Donnie growled at last. “I won’t ask again.”
“What’re you gonna do, run me over?” Casey chuckled to himself, but his voice had grown husky. “You’re such a brat,” he said, plunging an arm back in. The flat of his palm pressed firm against smooth muscle as he slid back inside and Donnie moaned, low and guttural.
“Atta boy, that’s what I’m talking about!” Casey rewarded him with another smooth, long stroke, fingers fluttering gently when he bottomed out.
Donnie was grateful for the interstitial fluid or motor oil or whatever was coating his insides because it made Casey’s movements feel smooth as velvet. If he still had eyes they would be rolling back into his head right about now.
“I can’t believe I’m saying this but you’re so fucking hot right now.”
“You’re not right in the head, Jones,” he said weakly. It was okay though - neither was he apparently. Really, he was in no place to judge.
“I can’t wait until you have your body back. I wish I could see your face too.”
Donnie was too far gone to fully unpack that, but the promise of more had him seeing stars.
Casey had started shamelessly grinding his hips against the front bumper, making his own attempt at friction. His breath felt hot against Donnie’s insides.
His engine growled to life at the sensation of Casey’s rutting. He wanted to touch him so bad. Pin him down and bite the soft skin at his neck, his shoulder. Kiss that stupid smile off his face and ride him into the ground… Fuck. He’d never felt this hungry for anything before.
Casey’s arm was unrelenting and he felt himself approaching… something. It was familiar enough, this sense of pressure building, even if the blend of organic tissue and mechanics made everything muddled. It was approaching fast though and blinding. The car frame rattled.
Casey flinched as static electricity hit his fingers and travelled up his arm. “Dee? You good?”
“Don’t stop. Please.” He wasn’t above begging at this point.
“I won’t this time, promise,” Casey whispered.
The instrument panel sparked. Donnie could feel his engine starting to overheat. There was an electrical pop and a groan of shifting metal as he crested over the edge. His mind went blank, every thought singularly focused on the white-hot pleasure flooding his senses.
Suddenly, he was in his old body again… laying on his back in the dirt with Casey sprawled wide-eyed in his lap.
“Holy shit,” Casey said.
It took a moment for Donnie’s brain to start working again. All rational thought was still competing with adrenaline and endorphins. When at last it returned his mouth started going a mile a minute. “This doesn’t make any sense, how did you - why did that bring me back?”
“Since when have our lives ever made sense? Guess you just had a lot of tension you needed to let go of, huh?” Casey was tracing his fingers along the lines of his plastron. “It’s good to have you back.”
Donnie was sure his face was embarrassingly red but he wasn’t ready to shove the human off him… not yet. He watched as Casey continued touching him, pausing at each little dent and scrape on the bony plates of his chest. It was almost as if he really had been worried about him.
“So about that payback…” Casey pushed himself up onto one hand and smiled down at him. He could feel Casey twitch against his thigh through his jeans.
This guy really had no shame.
“Come here you asshole,” Donnie growled as he brought him close again. He needed to save face. “This is a one-time thing, and we will never speak of it again, you hear me?”
“About that. What if we-” Donnie cut him off as he pulled him into a rough kiss, his other hand working on the fly of Casey’s jeans. Oh, it was so nice to have hands again…
※※※
Once the adrenaline had dissipated Donnie realized his hands were shaking. And he was dizzy. He tried to sit up and clutched his head with a groan.
“You okay?” Casey asked, reaching towards him.
“I think my blood sugar is low.” His stomach growled audibly as if to emphasize his point. It had been over a week since he'd last eaten anything.
“Oh! You need food, huh? Don’t worry Dee, I got ya.”
He let Casey help him to his feet and walk him to the house, one arm slung over the boy’s shoulder. The sun was low in the sky and a chill had settled in the air. Donnie leaned in closer to savor Casey’s body heat and the warm smell of his skin.
April and his brothers looked up as they entered the house, reacting first in shock, then delight.
“Woah!! Dee, you’re okay!” Mikey scrambled up first from the couch to tackle Donnie in a hug. “I’m so glad you’re back dude!”
“Glad to be back!” Donnie said with a tired laugh. Casey helped him walk into the kitchen to sit with the rest of the gang as they followed him to the table.
Once Donnie was settled, Casey went to the kitchen cabinet. “Hey Mikey, can you get Dee something to eat? His stomach's got a lot of catching up to do.”
“How did you do it Casey?” Leo asked as Mikey rushed over to wave a slice of pizza in front of Donnie.
“Trade secret. A little something I like to call percussive maintenance.” Casey grinned and shot Donnie a wink as he handed him a glass of water.
Donnie felt himself flush. Oh, he was so going to pay for that one later…