You couldn't resist it anymore and you didn't want to risk losing your humanity as you moved back close to the mare that used to be your girlfriend. She swished her tail again and her vagina winked at you enticingly as she lowered her head in defeat, knowing that your fates were now sealed.
You couldn't help yourself anymore as your horse penis slipped out of its sheath as you mounted the mare. It took you a moment to get used to your new anatomy but you pressed the tip of your new cock at the lips of her vagina. You paused a moment as you and your girlfriend exchanged a look.
"Go on stud," the Zoo attendant said with a grin as she leaned over the stall door. "You're not going to last much longer if you don't, or do you want to lose your humanity once and for all?"
You let out a whinny as the instincts pressed harder on my mind and you couldn't hold back anymore as you thrusted hard into the mare and she neighed loudly as you thrusted faster into her. You actually was starting to enjoy the sensation as you thrust in and out of her, the mare let out a whinny as she started to move with my thrusts.
Your mind started to descend into a mess of instinct as you thrust faster and deeper into your girlfriend. You were fully aware that anyone who came in could see the two of you but you didn't care, you were animals and you were going to act like them. You humped faster and harder before you bit down a little on the mare's shoulder and thrust one final time as your semen shot into the mare as her vaginal walls clamped down on your cock and drew out as much of your sperm as she could.
You breathed heavily as you pulled out of your marefriend and began to feel your human mind coming back. Your girlfriend turned her head back and looked at you apologetically and you just shook your head.
"Very good, very very good," the attendant said as she slipped the halter onto your head and stroked your mane gently. "Good horse, now you're both all set for breeding and turning more guests. Come on, I'll show you to your new home, tomorrow we'll get you all situated. You're going to make a fine stud and your girlfriend will make a good brood mare."
The attendant moved you into the stall right next to your girlfriend and set out some food for you. You started eating, occasionally looking over at your girlfriend who shook her head, you just had to hope that everything would be okay.