As she regained her sensed, Megan looked at her transformed body. She began to cry. Bill held Megan, doing his best to comfort her, promising to stay with her no matter what. When the tears finally finished, they held each other in silence.
As the initial shock and grief wore off, Megan realized she was incredibly hungry, no doubt caused by her massive increase in mass. She couldn't maneuver very well in the kitchen. Bill helped fix her a large meal. Her tastebuds seemed unaffected by the changes; she had no craving for grass or grain. She did consume several apples, but she liked those before all this started. The couple tried to make sense of what had happened and how they could deal with it. A call to Megan's scientist friend went unanswered.
That evening, they began to cuddle then make out. Bill's physical attraction to Megan had not been reduced at all by her changed form. Soon they were fucking, but as Bill held Megan's rear hips and pounded his equine cock into her equine pussy he felt something was missing. He wanted to mount her like a proper stallion. Bill still drove them both to climax.
Afterwards, Megan found it awkward to sleep on the bed in her new form and ended up on the floor against the side of the bed. Bill put a blanket over her, but laying alone in his bed he felt deeply unsatisfied. In his dreams, he was a full stallion, mounting his mare, Megan.
When Bill woke up that morning, he rolled over and stared at Megan, still slumbering on the floor. He knew what he wanted and he hoped it would work. Going to the bathroom, he found his horse testosterone PEDs. Giving himself one last look in the mirror, he took a triple dose.
Bill sat in the bathroom for a few minutes, wondering what to do next. Should he go for a run to help ensure things kicked in? He realized he was idling stroking his horse cock, which had gotten erect. It seemed even bigger. He stood up then fell over onto all fours. His body felt like it was starting to tear itself apart, starting with his ass. He felt his body stretching unnaturally. His balance was completely off as he struggled to his feet, bracing himself with the bathroom door frame. Then he felt it: his feet on the floor. His four feet. A look in the mirror confirmed he was now a humantaur.
Bill went to Megan, still asleep. He pulled the blanket off of her, got down on his knees, and began to orally pleasure her. Megan soon stirred. Bill helped her to her feet, but Megan couldn't see him behind her. Then she felt him mount her and his hands embrace her torso and cup her breasts.
"We're in this together," Bill whispered into Megan's ear. Then she felt him slide into her and immediately knew he had gotten bigger. Her stallion mounting her! She was so happy! She let out a horse-like sound of pleasure. The two humantaurs mated with greater physical pleasure than either had ever known before.