Esmeralda tugged gently on Duncan's ears as she kissed him, the teenage boy unaware of his lobes lengthening and becoming pointed, sprouting hair on their tips.
As their lips met, and their tongues intertwined, Duncan could feel his manhood stirring again, his young hormones racing as they urged his body to prepare for a second round of lustful love-making.
Pressing himself against Esmeralda, Duncan could feel the blood flow into his penis' shaft, his spongy cock hardening between them. Frustratedly, he began dry humping Esmeralda, urging his dick to hardness, his busy mind pausing to question why it wasn't completely firm already...even though the warm head had pushed up against his bellybutton.
Grinding harder, Esmeralda moaning aloud, "Oh, yes, take me, my stallion!" Duncan's dick forcefully slid past his stomach, and began to stretch upwards, towards his chest, its entire length hot to the touch, as if on fire. He could feel it thickening, its still semi-soft flesh expanding between Esmeralda's body and his own.
It was when it brushed against Esmeralda's breasts, and then slid between them, that he paused his humping, the realization of his dick's size and the sensation of its insertion hitting him all at once. Looking down between them, Duncan saw something that was nothing like his dick. It was far to big: thicker than a soda can, mahogany in color, its head was broad and flat. Thrusting upward, amazed, he watched as it pushed its way further between Esmeralda's breasts, the veins feeding it sending shivers down his spine as he felt his transforming cock beginning to reach its full erection.
Thick, viscous pre-cum began to spew from the python's huge head, and grinding faster, the sensation addictive, Duncan hardly felt his tailbone push out above his butt.
"I gotta get in you, Es." Duncan moans, almost whinnying in Esmeralda's ear, a part of his mind screaming about the changes occurring to him the other parts pushing his body's physical reactions forward.
Esmeralda lowered her head, her tongue flicking out to lick Duncan's wide oozing cock-head, causing the boy's entire body to convulse and quake. "You're too big, stud." she snidely remarks.
Body swelling, muscles tightening, becoming lithe and strong to feed his changing form, Esmeralda underestimated the lust she had imbued Duncan with...and the equine strength.
Grabbing hold of her, and shoving her into the bed, hair all the while beginning to sprout thickly down his back and neck, Duncan groaned, "God! Ugh! Babe! I need to get into you, NOW..." his uncontrollable cock incessantly grinding against Esmeralda's body, desperately seeking to penetrate her as his body's changes progress, his balls darkening and swelling in their stretching scrotum.