As Ty looked at Sam, he realized that he would never be able to fit his cock in her pussy as it was. Pausing for a moment, he came up with an idea.
"I wish that Sam's genitals will grow and change into that of a full grown mare, though nothing else about her body will change."
Sam gasped as she stared down at her pussy, the lips puffing up and darkening to a deep brown as it took on a more tear-drop shape, pulling towards her anus a bit more. Once the shape change was complete, Sam moaned as she felt both the external and internal parts of her pussy expand and then wink, ready for a huge stallion-cock to fill her, her slit already dripping pheromone-heavy mare juice.
Ty grinned as he caught a whiff of Sam's new pussy, his balls churning even more vigorously. Had he not already wished to remain flaccid, he was sure he would have already blown his load.
"Hung like a horse," Ty murmured as he stalked closer to Sam, breasts bouncing and balls swaying. Instantly, blood rushed to his cock, making it virtually explode out of his sheath. It hovered before his face, throbbing like mad and twitching in time with his heart-beat.
Without hesitation, Ty gently pushed Sam down onto the soft carpet. Grinning, he thrust into her in one smooth motion, barely giving her time to squeak in surprise. Pumping in and out in increasingly faster motion, they both moan at the enhanced sensations.
All too soon, Ty felt a familiar heat building up in the base of his shaft and after a few more hard thrusts, buried himself into Sam's slit, his balls churning and the head of his cock flaring as he exploded inside of her. That in turn set Sam off, screaming in delight.
As the two enjoyed the moment, Ty's senses slowly came back to him, and he pulled his rapidly softening cock out of Sam's sopping pussy. This just caused them to shudder even more, as the hyper-sensitive pieces of flesh rubbed against one another.
Panting, they looked at each other and thought of what to do next.