You look to the fairy, who still has that impossibly smug grin on her face, and neigh harshly at her. She isn't impressed at all, though. She even laughs. This must have to do with your bewildered expression that must look incredibly ridiculous on a horse. Chances are, you would have laughed at such a scene as well. But it is nothing compared to your appalling discomfort. Not only are you a unicorn, but you can't even speak anymore! You are just reduced to typical equine noises and... You look downwards, spreading a bit your long legs and from upside down you notice what's between your legs. Or rater, what's NOT there. Still not there. There is no sheath ready to reveal a big horse penis! Or testicles, for that matter! Just a... Well, a slit, you suppose. To receive a the penis of a male unicorn and taking it. The thrusts and pleasurable ejaculations won't be for you. What YOU can expect is taking it and getting pregnant, to have eventually something much bigger and unpleasant go through your vagina. Because without a doubt you must have the entire female apparatus that goes with it.
Enraged by your equine appearance of feminine beauty and dainty magnificence you neigh even more at the fairy, even jabbing at her with your horn, in the illusory attempt at impaling her. You are too slow, too clumsy. You are trying to aim with your forehead, after all. The fairy darts around you with extreme ease and flits about just to mock you.
"Well, since you need to learn to act a bit more as a proper unicorn, here you go!"
You receive another shower of fairy dust. Argghhh! What did she do now? You shake yourself vigorously, cursing the fact that you have no opposable thumbs or hands anymore. But then you feel... strange. Very, very strange. As if you were desiring something with all your heart and body. But what?
"You're in heat. Soon all unicorn males will catch your scent. Maybe living as a couple and being a loving mare shall teach you to appreciate your new role and life!"
She leaves you, giggling madly, and disappears between the trees. Uh-oh...