Ashley rammed her eight inch dick into Ty, pounding away furiously, the dildo still lodged up her tight ass. Ty moaned with pleasure, her hands running all over Ashley's body, Ty's mind awash with lust. Ty could no longer even think straight, as Ashley rubbed Ty's firm breasts and pert nipples.
"F-fuck, oh fuck..." Ty moaned.
Ashley saw her chance.
"You like it, don't you Ty?" Ashley whispered sensuously.
"Oh fuck yeah," Ty gasped in her new, feminine voice.
"You want me to do it even harder, even stronger, don't you?" Ashley added, pounding away with her cock.
"Oh yeah..." Ty moaned. Ashley could feel her body strengthening, her muscles hardening. But she remained female.
"You want me to fuck you with a big, studly, manly body, don't you?" Ashley suggested alluringly, even as she rammed her dick home, using her greater strength.
"Oh fuck yes..." Ty agreed. Ashley could feel her body changing, gaining new angles, losing its softness. Ashley decided to push it all the way.
"You want me to be Dustin, don't you? A big, strong, powerful man with a big, strong, powerful body and a big, strong powerful cock - isn't that what you really wish for?" He asked, his voice still deepening as he became fully male.
"Yes!" Ty screeched, lost in pleasure from the fuck that Ashley was giving him. At that word, "Ashley" fell away, becoming Dustin once more. But he didn't just revert to his old self. He aged until he was eighteen. But he was no ordinary eighteen year old. Thick, strong muscles swelled all over his body, hard and round, full of power, until he looked like a young bodybuilder. His dick grew even larger as he pumped it into Ty, becoming a foot long monster, thick and hard. Ty moaned and squealed with delight as it filled her even further, stretching her young pussy as her hulking brute of a lover pounded it in with his powerful new body. Dustin's huge fuckrod began to shudder as he came close to cumming, his big balls churning eagerly. With a grunt of power and pleasure he came at last, pumping a huge load of cum into Ty's tight love canal. The orgasm caused Dustin's powerful muscles to contract, and he rammed away at Ty harder and faster than ever, driven to a frenzy of lust, as Ty screeched with pleasure, assaulted by a series of orgasms more powerful than anything she had ever known.
At last, Dustin began to slow, long after the last of his seed was spent. He gently lay atop Ty, his huge body heavy upon the much smaller woman, his thick cock still shoved up her sex, but slowly retreating as Dustin's hardness subsided.