Pride and a foolish fantasy driven desire got you this far into your troubles. Primary troubles that you being an animal and Jackass-mule as your physical form, and this means you became as property, and worse, owned as such by a ruthless wizard. Your mind is warping, you know that from having been changed those memories and learned intelligence is bound to begin fading. Thinking has its times when animal instinct wants to be in control, and you need then to stand and work out a problem by considering, reasoning, thinking then as would a human.
Indeed, sleep is the only method by which you can indulge your desired fun fantasy and see yourself mingling with and mating, stand as mounted, cock inserted, you thrusting, being engrossed in equine JOY.
"Hey, wake up," the old wizard says, as he using his boot give you a harsh kick in the gut to stop your wonderful dreaming.
The wonderful scene of your dream is still within the focus of your mind as you scramble the four legs to boost the bulk body into a standing position. As you rise up and then gain a full stance, you feel and the Wizard takes note that your Mule size cock is in a stout state of an erection.
"Ha, equine dreams aye there buddy boy, but not the balls to make the reality as your future endeavors. Yea, I know true enough you being as you are, you could court a mare, mount a mare, but after thrusting inside her hot tunnel of sex, nothing comes, no semen, no sense of sexual release, no slackening feeling to enjoy an afterglow, just a sense of lust. Lust, lust, lust is what controls animals, and that instinctive wish to procreate.
Hear me," the wizard said, as being a brute he again uses his foot in his boot and gives a hard swift kick at your stoutly erect cock. "You listen and get this good, me, I own your sorry self, you are a beast of burden, a animal slave, and nothing more. If you do as I demand of you and work to pack my belonging over these mountains, THEN, and only then might I divine to you your big balls, and sell you to some farmer as a trusty stallion horse.
You fail to owe up to my needs and expectation of you, and your future is the same as any other Mule!"
A bowing of the head three times was but your way to agree and make the head motion as if nodding a YES answer, a promise to be faithful.
The old man wizard is not without his sense of justice and offers then the feedbag filled with raw oats.
As you stand there munching your Mule style breakfast, the wizard says, "Some years back it was..., yes, when I was somewhat younger. I felt the occasional urge for want of a female to fondle, suckle, and let me sexually molest her until she lay on the floor begging me not to do her again. As I would have dreams and get morning wood similar to yours this morning.
One young woman, her femininity was very loose, and my cock shoved inside her seemed puny. I am not the kind to feel puny no matter what, and so I spellbound my cock to be like the size of yours and she then swooned as I thrust inside her. She told me of her need to work as live and earn food a landlord had her in a show where she needing, was given a donkey Jack to let it mate with her.
She had become then loose and able to fit inside her vagina the cock of a brute beast, and she learned to like the sensations. When came the next morning and as she laid there all warm and smelling sweaty, I had a thought what made me smile. As my way to give her an awarding for a wild night of several orgasms, and since I had no real desire or need for a female companion in my travels, I cast as deep a spell as I knew then how and caused her body to change.
Ha, I granted her a sense of peace but at the cost to her of her sleek, slim body and big breasts. As from where there that Inn was, the locals used Belgian draft horses to do most everything that required strength on a farm. I cast her into becoming as a Belgian yearling mare. So when she awoke and feeling odd, she stood up, became aware of her changed body, to my surprise, she actually liked, as appreciated my act of generosity.
I sold her for quite a tidy sum, and she being then a horse, mare and not a whore, did whinny at me her thanks, and pressed her face to my chest as nuzzled again her thanks, she made me feel good I made of her a horse with a vagina that she could enjoy an occasional stud.
So then humor me well Mule and maybe, come we get onward and arrive safe as sound, intact to where I am going and I might restore your balls, maybe!"
I ate and listened, knowing what and of how I should do, as then the oats were gone my cock grew out its sheath, as hung there limp but weighty plump, so I did take a piss and watered the roots of that tree he pissed on the previous night. It was when the old wizard did untie the rope rein from that tree when I noted something that offered me some new wisdom.
Magic had made of me to being equine and then a mule. My Mule piss had entered the tree roots and there on the tree trunk was sprouting of millions, billions of tiny horse hairs, as soon the tree would have a furred pelt to keep it warm.