To GM
Despite the magical compulsions, and despite his own rising arousal at having his will taken from him in such a way, he found himself getting rather pissed. He had no problem submitting...but on his own terms, and of his own free will. This little piece of shit was simply doing with him as she would without any thought of his own desires, and he did not approve of that.
However, he wasn't exactly sure what he could do to resist. He was in no position to be able to fight back against the horse, so that at least was going to occur. However, he had didn't want to sing about him enjoying being taken by a horse. He sent a silent prayer up to his god, swearing to make the proper offerings as soon as possible if he would assist him with this turn of events.
At the very least, if he did end up singing, he planned to do so in his most unpleasant voice he could bring to bear. Perhaps makign everyone want to claw their ears out would be enough to get someone to intervene.