Ty embraced the weirdness. It was clear they were both consenting creatures. He dropped his underwear and felt his five inches swell against the freedom of the warm summer air in the room. The smell of hot hadrosaur sex hung heavy in the room, enhancing everything further.
Paris stared, cocked her head, and smiled. She closed her eyes, took a deep breath, and grinned snout to snout. "All right, my creator, I guess we're going to go all the way."
"We are." Ty whispered nervously, blushing deep red as he gripped her raised tail, guiding it over his shoulder as she lowered her ass down to meet him. It didn't even take a push. The moment Paris maneuvered her vent toward Ty's dick he slipped into her hot folds, a little puddle of her juices forming under them as she dribbled down his balls. He reached down with his hand, guided himself in and down, and hit the slickened passage within. Paris stepped back carefully. She was getting really big now, almost as long in the body as Ty was tall, and with a delicious slurp Ty slipped into her without resistance.
They both blushed as the two jointly felt their first experiences of joining in sexual congress. Ty began to thrust gently into the dinosaur. If anything, they had waited long enough that she wasn't as tight as he had expected, but it still felt amazing. Her heavy tail over his shoulder, they began to press into each other gently, Paris well aware of her strength and holding back from slamming the human onto the ground with her weight. As she grew, they began to get a little more assertive, and together they began to build rythym.
"Y-You good?" Ty sweated. He was sure good. Her delicious wet folds were hot and swollen. Despite her increasing size she was still exerting a huge amount of pleasure on his young cock.
"Very good!" Paris panted. "Very very good! You feel great! Y-You don't have to be so gentle."
Ty trembled as he thrusted harder and harder. The big hadrosaur could take it easily. They both began to moan. Ty grabbed her now huge muscular thighs and pulled her closer. Her constant growth meant they had to readjust to her size. Ty realized her scale compared to him now and laughed in delight.
"Getting so big!" He gasped.
"I know!" She turned in delight, eyes lit up. "Look at me! I'm gigantic!"
This spurred the human on as he felt increasingly tiny before the growing dinosaur. It came to the point where Paris had to kneel on her great muscular legs in order to keep Ty inside of her, and for the human he felt her vaginal canal loosen considerably as she grew. Still, he angled himself to her hit the slick bottom wall of her pussy and gave her everything he had to give.
Paris mmphed and moaned. Whether it was for show or because she actually was getting something, Ty couldn't tell. All he knew was he was fucking a giant growing parasaurolophus and it felt amazing. Finally, unable to hold on anymore, he grabbed her round thighs, thrusted deep, and gasped as he came. Ty saw stars. Paris hooted loudly.
When Ty opened his eyes he was gasping and spent. He fell back onto the edge of the bed and his eyes widened in natural shock as he saw his pet dinosaur was truly huge now, starting to fill the room with her immense muscular bulk. Ten feet long? Twelve? Fourteen? It was impossible to tell. All Ty knew was that when he stood up in front of her grinning face, her head towered over him and nearly hit the ceiling.
"Should... should you stop me?" Paris looked around nervously. "I'm having the opposite experience now." She giggled. "You did say you were going to grow me nice and big."
"Was it... was it at least nice?" Ty gulped anxiously. "I mean, you're big now, and I'm not."
"I definitely felt good." She smiled. "I think it would have been better if you didn't do the tongue thing first."
"Oh!" Ty grinned. "Oh, yeah!"
"Uh..." Paris finally bumped the ceiling with her crest and bowed down sheepishly, her tail knocking something over on the other side of Ty's room. "I'm... I'm really getting large now, Ty. Are you sure you want to let me keep growing?"