Mike was lost in the mating act until he shuddered in release, pumping his seed into the big Shire female. He shook his head and moaned as he lay heaving over the back of the mare, then slowly slid off and pulled free. As intense as the experience had been, he realized it must not have lasted very long. The stable boy was still in the same spot, grinning at him.
"So, have fun?" The boy walked over and patted his equine side. "Stallions come pretty quick. Part of the prey animal thing, I guess. Can't spend too long at anything, even sex, in case something out there wants to eat you."
"Uh, yeah... I guess." Mike was still dazed, feeling thick-headed, but also very satisfied. It was like he had just done something that was incredibly important - he might just as well have won the Nobel prize. "That was amazing! I feel incredible."
The boy grinned and reached under Mike's belly to heft his penis, which was still partially erect. "I expect she'd enjoy another round. Wanna try for two?"
Mike was confused - there was something weird about being in a stall with a mare, having the boy handling his maleness, and his face and arms were feelings sorta odd. Not bad, just different. Still, the mare's scent was inviting and he felt himself start to get hard again. If he could just clear his head. But she smelled so good...