as far as stretching and fitting goes.... I'm surprised so many think it would be an issue.... Bare in mind, that even though a horse's cock is big, a baby is bigger by a long shot.
True but when birth is involved there are also tons of hormones involved to cause dilation and aid in 'making room'. Unless you are a woman used to taking large objects something the size of a horse would require time to accommodate. Of course all the time in the world would not be enough for me to wedge that in.