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I Wonder How Your Engines Feel
🕑 Added 2025-02-06 04:45:31 +0000 UTCDisclaimer: This story contains adult themes. It is not suitable for minors or the easily offended.
https://linktr.ee/spartacuswrites
Contains: Breast Expansion as Weight Gain
Read more of Mary’s story in Karaoke.
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I Wonder How Your Engines Feel
Mary and Karly followed Cassidy down the grandstand steps to ground level, where a car plastered with branding sat idling on the side of the track.
“Here she is,” Cassidy grinned, waving her arms proudly.
“Are you sure this is safe?” Karly asked.
Mary knew her partner wasn’t a fan of car racing or motorsports in general. She wasn’t really, either, truth be told; neither of them had much time for sports at all. But Cassidy’s enthusiasm was infectious. She’d never hooked up with an adrenaline junkie before, but the woman’s competitive nature had gotten her to an L-cup the previous night. Cassidy wasn’t as good as the older guy she picked up at karaoke, but no one had been, except for Karly. It definitely wasn’t going anywhere long-term, but she was having fun.
“The track is closed, and I’ve driven it hundreds of times,” Cassidy said. “It’s perfectly safe.”
“I thought these didn’t have passenger seats,” Mary said.
“They normally don’t, but I had my crew install one they can take out for race day.”
“Does it have seatbelts?”
“Quit being such a mom, Karly.”
“Both seats have five-point harnesses,” Cassidy said.
“Fine, fine.” Karly held up both hands. “Sorry.”
Mary leaned in to give her partner a quick kiss. Karly’s eyes flicked down. Mary was up to a B-cup; the cocktail of thrill and anxiety already had her worked up. Karly smiled warmly. “Have fun.”
Cassidy helped Mary slide into the passenger-side window, then leaned in to connect the harness straps. Mary was pretty sure the process didn’t usually involve so much touching and stroking, but she wasn’t complaining.
She saw Karly walk to the first row of bleachers and sit while Cassidy climbed behind the wheel and strapped herself in. Cassidy grinned as Mary met her eye. “Ready?”
Mary nodded, and Cassidy revved the car’s engine. The low, steady rumble increased to a roar, sending a thrill up her body. She could sort of get why guys got so into stuff like this.
The car rolled into motion, gliding smoothly onto the track itself. Cassidy took them slowly to a solid white line Mary guessed was one of the starting positions. “It’s kinda like Mario Kart,” she said.
“Heh, want to count me down?”
With both hands, Mary gripped the straps running from her shoulders to her navel. “Ready?”
Cassidy nodded.
“Three… two… one… Go!”
Mary was pressed back into the seat as the car shot forward. The motor’s roar was almost deafening, and she was thankful for the earplugs Cassidy put in her ears. The car’s vibration massaged her entire body—sitting on a washing machine paled in comparison. As Mary’s loins tingled, she felt her breasts slowly start to swell.
They reached a corner, and Mary was pulled toward Cassidy, the harness squeezing her legs and bringing her to the brink. When they straightened out, Cassidy looked over at her with a lascivious grin. She glanced down at Mary’s chest, licking her lips. Mary looked down herself, and though it was hard to tell with all the shaking, she guessed she was up to a D-cup.
Cassidy was relentless, taking them around and around. With every corner, Mary got closer to release. Every time they went straight, Cassidy pushed the engine harder, making pinpricks of bright white sparkle in Mary’s eyes. The shoulder straps of her harness were pushed closer together as her breasts swelled, joining over her sternum.
Just before another corner, Cassidy shifted gears, then placed her right hand on Mary’s thigh. The touch was barely noticeable in her world of roaring, vibrating bliss, but it was enough. As her body pulled against the harness, Mary came. Just when her release started to ebb, the car started to slide. Mary’s guts dropped as her world spun along with the car. The panic and fear unexpectedly made her orgasm stretch, ecstatic pleasure rocking through her body as her breast exploded in size. Cassidy jerked her hand back to the wheel, stabilizing their spin and straightening the car with a few wobbling fishtails as they came out of the turn.
The racecar slowed, the harness squeezing her against the seat, and Cassidy took them back to the pit, where Karly stood wide-eyed. Mary took deep, gulping breaths as she floated back to lucidity. Her breasts filled the space inside the car, almost resting on her lap. Still shaking, she looked over at Cassidy, who was watching her with heavy-lidded eyes. “I… I think I made a mess in your seat.”
Cassidy popped her harness open and climbed across the car to take Mary’s mouth in hers. Her hands were everywhere, and she murmured, “You’re incredible…”
Karly’s voice from outside Mary’s window cut their celebratory makeout session short. “What the hell was that!? You almost crashed!”
“Relax, Karly. She did it on purpose, didn’t you, Cassidy?”
The driver’s cheeks flushed. “Um, yeah, totally!”
“See? We’re perfectly fine. She’s a professional.”
Karly sighed. “Well, that was the most stressful thing I’ve ever had to watch,” Her eyes flicked down. “But… I guess I can’t argue with the results.”
Mary smiled up at her partner. “It was soooo much fun, Karls. You should try it!”
Karly held her palms up. “I’m good staying at the speed limit, thanks.”
Mary and Cassidy laughed as the driver undid her harness, carefully extracting the straps from around Mary’s enormous melons. Cassidy said, “Thanks for letting us do this, Karly.”
“No problem, as long as Mary had fun.”
“I really did…”
Mary’s body felt so spent she wasn’t sure she could stand. Karly, however, identified a more immediate concern.
“Um… how are we gonna get you out of there?”
