Megan nickered a little as she felt the heat rising in her loins again. She had been feeling a growing desire to be mated, and the longer she waited the harder it would be to resist the advances of the other stallions. She was Alan's mare, having submitted to him already, and now all she wanted was to be bred. The human woman that she once was was gone, but that didn't take away her loyalty to him, even if she knew that he would take more mares, she was going to be his first.
She smiled as she moved away from him finally and raised her tail to expose her winking slit to Alan. He felt his cock slipping out of his sheath, his desires growing as he moved in close and breathed in deeply. He could smell the pheromones from the mare's pussy, his cock now at its full length, his instincts telling him to mount the mare, and he quickly gave in, raising up and falling on Megan's back as he thrust forward, trying to penetrate her with no luck at first until finally hitting his mark, causing Megan to neigh loudly as he did.
A few of the attendants watched as the two horses mated with one another. Despite his inexperience with his new body, Alan quickly got used to it, his large balls penduluming back and forth as they slapped against her backside. His cock filled Megan's tight pussy, her muscles clenching down a bit as he thrust faster and deeper, the mare felt so amazing to him as he prepared to breed her. There were some flashes of his old life, but they too faded, leaving only the stallion and a desire to mate and breed the mare beneath him as he thrust deep into her again, filling her with every inch of his cock as he whinnied loudly, nearing climax.
Finally Megan whinnied loudly as her pussy clenched down on him, her juices coating his cock as she did. Finally, Alan thrust in one last time, neighing as he came hard, filling her insides with his seed. The two horses panted as he slowly started to pull out, falling on the ground next to her as he nuzzled Megan gently.
There was nothing left of the human couple that had once been there, leaving only the two horses once and for all. Megan nuzzled him back as their mixed juices dripped down her hind legs, happy to have been bred by her stallion and hoping to now be carrying his foal.
The attendants smiled as they watched the two for a long moment. They walked over and lead them out into the pen outside with some other horses so they could relax a little.