John moaned and grunted as his testicles and cock stretched and expanded. His package stayed human, but grew twice as big. John’s length was a modest 7” before, but now, his penis was at least 15” and had the girth of a tennis ball, not to mention the thick veining. His balls, on the other hand, were now the nice of softballs and sagged almost to his knees. It all throbbed with need.
“Oh my~” Kayla said in a low tone, covering her mouth with both hands.
John stood in shook, looking down at his new upgraded crotch. “What the-“
“John,” Kayla started, as she turned around and lifted her long, black tail to the said, revealing her big, black, horse anus that was slightly leaking John’s cum, “how about round 2?”
Kayla winked her asshole at John like a mare would wink her vagina at a stallion while in heat. John’s cock throbbed harder, and without hesitation, he climbed back up on the stool.
John grabbed his massive erection with both hands and carefully lined it up with the donut hole in from of him. He placed the tip up against Kayla’s cum-covered opening, grabbed her fat, furry hips, and pushed in.
“Oooohhhhhh!” Kayla moaned at the sensation in her rear, “this is soooo much better!”
John felt that, too. His new cock was gripped so much tighter but Kayla’s walls. It felt like she was milking him with her insides.
John slid his length in and out, not only making a ‘plop’ sound as his naked thighs met Kayla’s furry buttcheeks, but also as his long hanging testicles met against Kayla’s black, leathery sack.
Kayla’s erection throbbed even harder than before, occasionally slapping hard against her belly, causing pre-cum to drip out. Her tight asshole was starting to stretch from John’s girth, but she knew he’d be finishing soon. As a matter of fact, so would she be. Her balls tightened and churned and finally-…
“Ahhhhh!” Kayla screamed, as she orgasmed again, even harder than before. This time, she coated all her under fur and back of her front legs with her hot, gooey horse semen.
John didn’t tell, but rather moaned and grunted, as his balls tightened up tight and he began to dump load after load into Kayla’s equine ass. So much so, that her ass couldn’t hold it all, and the spunk began to run reverse through her insides and flood her stomach.
“John! You’re REALLY filling me up!” Kayla said in excitement, as she looked over her shoulder at her horse body to see her sides expanding.
“Al…most… there…” John grunted as he held on tight to Kayla’s horse hips, still flooding her.
By now, Kayla’s horse body looked like it was ten months pregnant, and the with John still pumping and the semen needing more room, it continued up into Kayla’s human stomach.
“Oh my god, John!” She cried in excitement, placing both hands on her flat, toned stomach that was now beginning to swell.
“And… there!” John said in relief, his balls finally empty. His half flaccid cock popped out of Kayla’s asshole again, this time, a steady stream of his cum shot out right behind it and all over the tack room floor. He looked up at Kayla.
“Oh… oh! I’m so sorry! I had no idea I was that full!” John said in a panic.
“No, no! It’s fine! I’ve never felt better!” Kayla said with a smile, trying to calm John.
The centaur girl stood there, her human stomach looked pregnant with triplets and her horse belly looked pregnant with twins. Kayla’s cock hung flaccid, still leaking cum into a puddle beneath her. She rubbed her belly.
“So John, now what?” Kayla asked.