Her cervix teased your glans with harder thrusts. The mucous slick donut tickled your very tip and made you flare uncontrollably in an attempt to grow the last fraction of an inch. You’d never considered yourself big by any means, but her biology was optimized for normal equine mating which included a longer penis, but also a less efficient mounting position. In the end your flexibility won the day and allowed you to give your mare the experience of her life. You hilt again before grinding deeper into her body.