My fingers began to be forced apart by my growing dick; my manhood, the fleshly tube projecting from my crotch, rapidly thickening in my large palm. Huge veins snaking across its surface, its girth already greater than any soda-pop can, I couldn't resist letting a pleasurable moan escape from my lips...no, wait, it wasn't a moan, more a whinny. Back muscles quivering, it felt like my cock was on fire, its weight in my hand exponentially increasing, so smooth and spongy, elongating, its fat head already drooping a good eight inches from my grip. Skin darkening on it, tanning, becoming more ebony in color, my whole body shook at it continued to stretch and grow to awesome proportions, arousing lusts in my mind about its dimensions when fully erect. My balls also grew, my scrotum expanding to accommodate them as they first swelled to softball sized, then cantaloupe sized spheres, churning as they filled with my new seed.
Mushroom head flattening, my cock's shape changing, I watched in fascination the changes occurring to my dick, unaware of the transformation also besetting the rest of my body: the fur sprouting, my muscles tightening, and my toes fusing into hooves. My progression into a werehorse was underway and although my penis had begun to fill with blood, further heightening my burgeoning animalistic horniness and primal needs, whether the changes would continue pleasurably or painfully I didn't know.