Corey's penis had been modest before. Not that Kyle had ever cared about his brother's junk. It was just that the torn scraps of underwear that covered it moments ago had been enough to contain it with room to spare.
The crotch of the briefs had been torn out by the thickening member as it grew, the tighty whiteys held on only by the strap of elastic running around his waist. Kyle eyes bulged, every sensation in his own body surging out from his own horse cock. He licked his dry lips, breathed shallowly as thick veins threaded their way across Corey's velvet flesh, more and more blood pumping to fill the expanding organ. His sac turned a dusky, leathery tint as the balls inside grew to fill it, and then the scrotum itself thickened and ballooned out to accommodate them.
"K- Kyle ... " he gasped, his voice cracking. "What-"
"It's all right Corey," Kyle said breathlessly. He finally took his hand and softly grasped the increasingly inhuman cock, drawing a groan from his sibling. His hand could still wrap fully around the shaft even as it inched higher, every beat of Corey's heart matched by it expanding further. A burst of clear pre rose from the flattening tip and flooded down the sides and over his fingers.
By now, any conscious resistance Kyle could have mustered was gone. He pulled forward and drew his tongue along the slick horse flesh even as it changed color, patches of black and pink sprouting along it. The testicles grew to the size of softballs, then oranges. Stiff dark hairs sprouted around the dark skin. A salty, barnyard-like scent began to rise from them. Kyle was seized with the memory of 4-H field trips and state fairs from years ago, wondered how he ever could have found it unpleasant. His attentions reached the tip of his brother's cock, just as it reached the peak of its growth, his tight grip forced apart as it grew as thick as the fourteen-year-old's calf. Kyle put his mouth over the flat tip and suckled hungrily at the stream of cum. He ran his hands up and down the cock, felt his brother's legs jerk and rub against his own, thrust his hips against the warm body beneath as his stallion member erupted.
Ropes of cum ripped out, landing over Corey's member and chest and face, over the floor, against the door to the bathroom Kyle had hoped to lock himself in in what seemed an eternity ago. He inhaled in a deep snort, released a high shrieking whinny from his throat.
One of his hands kept squeezing at Corey's penis, the other found his smooth chest, shellacked in cum, and clawed through the mess. Corey had reached the peak of his change, and his limit.
" ... oh ... OH ... " The boy's voice rose into its own equine whinny as he exploded beneath his older brother. Thick, viscous cum, thicker than anything his furtive experiments in masturbation had extracted up to this point, tore out from him. He thrust his hips up in suffocating joy, smashing the tip along Kyle's face and spraying cum in all directions as he writhed. It landed along Kyle, the floor, the walls, the family photos decorating the hall. The shared ecstasy drew on for what seemed an endless period as the young bodies shuddered and jerked against each other.
Kyle collapsed over Corey, their slick bodies forcing the obtrusive horse cocks to slide aside. They lay chest to chest, breathing greedily, seeking some brief window of lucidity as the unnatural lust abated for just the time being. Not that it went away. It stayed, a coiling, burning presence as unavoidable as the soft heat of the insanely large cocks resting between them.
Kyle shut his eyes again as he panted. Even now the guilt wouldn't come. It wouldn't have time before the animal need rose again and drove him, and now his younger brother, to sate it.
This was all because of that cheerleader, he rued. Like she'd put some kind of-
... curse!
He snapped to and pushed himself up. Understanding flooded him as violently as everything else he'd gone through this morning. The curse! He'd called Jennifer to place the curse on her and she'd turned it around on him! That meant, and he had no more reason to doubt the old stories, that he still had the power to cast it!
"Oh my god," Corey moaned. He'd rested enough to open his eyes and understand what had just happened, the warm and pleasant throb between his legs reminding him. "Oh God ... " His eyes took in both alien members sandwiched between him and his ... naked ... they were both ...
A hand clasped over his mouth. Kyle looked directly into his eyes. He looked ready to cry, but his jaw was set in determination.
"Corey ... transform or dare?"