Father had a small shed built out back behind the house, as a place where donkey Dan could stay to live from day to day for a year of being as his animalistic self. Dad had some men come and placed a four foot high chain link fence around the whole backyard, as giving Dan a place where he could graze.
Mom cast a spell to rejuvenate the backyard grass to being extra green, completely weedless, and grown each night to being four inches tall come the morning. Dan found his daily lifestyle as generous, granting him an abundance of greenery for him to graze and grow, he maturing to near full grown as a donkey Jackass after just nine months of donkey style delights.
Unbeknown by the parents of Dan and Kat (Katherine) but Kat liked to visit her nearly dumb animal donkified brother when their parents went to visit friends. Kat came prepared when visiting her brother, as she had with her KY jelly to help stimulate Dan, as she would masturbated her donkey brother to enjoying the sensations of when he would climax.
Kat continued to add new spells that enhanced her donkey brother, one what made his donkey balls to swell, becoming similar of size to those belonging to a Zebra stallion. She spellbound Dan with increased semen production, as he and she enjoyed the bucket full of semen he would ejacualte when mom an dad were not there to see or realize what Kat was doing to her brother.
As Dan gained more masculinity of being a stoutly healthy and big donkey Jackass, his realization of past self occasionally surfaced during a masturbation session climaxing. Dan knew Kat as being his bestial benefactor, and as his donkey cock rose high, it ready to spew another mighty load, he with his equine style libido did try to direct the flow of semen to engulf Kat about her face. Dan tried his desired wish to poison or infect his witch sister several times attempted, until with a four spurted blasting load he caught her while she was mouth open and frantically laughing.
One blasted stream of donkey yellow, donkey creamy semen shot in a harsh as hot stream from the rounded hole at the end of his trumpet bell shaped cock-head, as the most of it did enter the open mouth of one evil sister.
Dan brayed happily as to what he heard when Kat began choking, she coughing, trying hard to spit out what had entered her mouth and gone down her throat.
"HEE-HAW, Hee-Haw, Hee..., Hee, Hee-Haw!" Dan brayed, he excited from what he knew he had accomplished, as had infected his damning sister. Even if from his semen having then doomed Kat and damned her to become as she did to him, his certain doom to remain a donkey felt worthwhile if Kat became for him as his first jennet to impregnate.
Kat ran from the small barn and stuck her face down into the watering trough for her donkey brother to drink. She gulped water, as tried hard to puke out the infecting semen, but everything tried went wrong.
As Kat stood leaning at her waist into the watering trough, Dan came up behind her and using his broad nostrils he did give her a hearty snorting blow at her rump and more sensual privates. The snort made Kat to jump as she did a full forward roll and flopped head-long into the watering trough. As she stood up, what water entered her mouth she did swallow, as did the semen go down to where she could not puke it out.
"You bastard, what did you do to Hee?" Kat yelled, as her last word said mimicked how Dan knew how to bray, as was left to braying like the donkey his sister made of him.
Obviously upset, Kat standing nearly waist deep in the watering trough for Dan, she began to stomp her way to the end of the trough. As she did raise her right foot and leg up over the high rim of the trough, Kat slipped, as fell head-long over the side of the steel tub.
"Oh crap," yelled Kat as she fell face down into the mud surrounding the trough tub. As she struggled in the slippery mud to gain a sound footing, she slipped, falling face first as bent over forward over the trough tub side.
Dan stood near watching, he amused by his clutz of a sister. When Kat had her butt up high and legs spread wide from her falling in, Dan had a wondrous male donkey inkling. If he be doomed and damned to be permanently a donkey, then as then was his best chance to assure his sister would follow him into a lifetime of beastly existence.
Kat screamed when she felt Dan sniff at her wide set rear. She knew what he was planning, but before she could right her self from bended over the tub side, a hard as boldly blunt male member of her donkey brother did rip open her wet as silky panties and did ram up inside her sensual depths, his donkey cock. As Kat held with her hands clamped onto the tub side she felt her hymen break, as a stout cock deflowered her. Dan felt the short depth to his choice female and took to thrusting ever so slowly, making sure he did not retract his cock too far backed out that it fell out of Kat before he could ejaculate and damn her as she had doomed him.
It was about two O'clock in the early morning hours when Mom and Dad had returned home. They saw Dan their donkified son standing near the fence by the sidewalk leading from the garage to the house, and Dad took note that his donkey son was sporting a mighty stout erection.
"Hmm...," moaned a non-magical father as seeing his animalistic donkey son sporting a stiff hard-on at 2:00A.M.
As Mom and Dad did enter the house, they saw there a teary eyed Kat sitting at the kitchen table, her head bowed, but her new donkey shaped ears standing tall as furry, they pointed and telling her mother as what happened that night.