Spreading Transformation REDUX - Part 4 - Mates
The rush of equine hormones from his throbbing balls into his hotly pumping blood was instructing him to keep her under control so she would bear many foals, no rivals could or would challenge him.
Just a Hookup
My other paw wandered around, alternating between stroking my leaking cock and groping my throbbing balls.
Whoops! I cut your dick off.
His cock spurted his cream deep inside the fox, the excess dribbling over his throbbing balls.
Ander - Part 6: Subchapter 147
It was a sound that instantly awoke the deep, throbbing pain in her back, turning it into a screaming, throbbing ball of agony with roots going all the way into her spine, forcibly tearing the last vestiges of her dreamlike state to ribbons.
Ander - Chapter 7, Subchapter 30
Her cheek was a throbbing ball of agony, and the bitter taste of blood was oozing over her tongue. the bone-chewer was still straddling her, nearly crushing her with his weight, holding his shaking fist up for her to see.
Getting Back to Work
Not much bigger, only about two inches or so - something he could have done to himself - but the throbbing balls just beneath it were definitely bigger.
Bound to be a Breeding Stud
Yet it was all alright with his need throbbing, balls aching, tightening, tensing - and then unleashing his seed in the thickest, headiest spurts yet.
His Mother's Friend
balls as they emptied into her, the woman panting "good boy caspian, give it to me, give me all you have, fill me up," as she felt a warmth pool inside of her, more than her much bigger (at least, in build, because the colt's cock dwarfed his) husband 
"Repossession"
She gave him a reverberating snicker and lowered her fangs to his throbbing testicles. he could only cry out in pain. she reached for his paw and led it to his testicular pouch. "you feel these??"
Goldenmane Chapter V: Nobody Expects the Spanish Inquisition
Likewise, more wires cascaded across the stallion's body, one ending in a loop just under number seventeen's thick flare, two more taped to the base of his throbbing testicles.
Pick-me-up
He came harder than he ever had, throbbing balls pumping his very soul out until there was seemingly nothing left in him. once he was fully past his orgasmic bliss he let go of his grip on teela.
Ander - Part 6: Subchapter 121
Her cheek was a throbbing ball of agony, and the bitter taste of blood was oozing over her tongue. the bone-chewer was still straddling her, nearly crushing her with his weight, holding his shaking fist up for her to see.