Erica pulled away, licking the milk from her lips. A chill ran through her body, and she fell away from her sister's udder. Hair started appearing on Erica's arms and legs in massive amounts. It was thick and dark, unlike the cream colored hair that covered her sister's body.
"Maria....what's happening? I'm...something's not right here." Erica said. There was a pulsing sensation in her pants, more specifically her crotch. She tore her pants and underwear off as the sensation got stronger. Erica looked down and saw something growing from her crotch. It was cylindrical, about three inches long and it felt hot. Erica didn't understood the feelings emanating from her crotch. She felt....good... Really good. It was a weird sensation, she had the urge to touch the thing growing from her.
The dark hair around her crotch spread to the meet the hair on her arms and legs. The hair was quickly spreading over the rest of her body, which was bulking up and transforming from that of an 11 year old girl to a mature male. Erica was so busy pleasuring herself she didn't notice. She ran her hand up and down the length of her new appendage. It was growing at an alarming rate. Her fourteen inch cock matched her larger and stronger body.
Meanwhile, Maria was busy stroking and tugging her teats, milk flowing freely. She was oblivious to Erica's changes. Her own pleasure was consuming her. Erica heard a mooing, and saw a female cow creature fiddling with its udder. Horns erupted from Erica's head, and her face pushed out into a bovine muzzle. A tail extended from her back. The transformation sped up as Erica's arousal grew. Her barely noticeable vagina completely closed up as two testicles formed. Starting out as the size of eggs, they ballooned to the size of softballs. Encased in a thick, leathery sack that hung down by her large thighs, they swelled with cum.
Erica's feet burst through her sneakers, now hooves. Her chest now featured well toned pecs, her arms looked like they had footballs beneath her skin. She was now a he. Erica bellowed as he had his first male orgasm. Cum flew across the room and the sounds of happy cows filled the bathroom. Maria felt her udder bloat and then explode milk. It mixed with the cum on the floor. Now that the two cow creatures were satisfied, both were very aware of their current situation.
Maria and Erica looked up at the same time and screamed in surprise and shock when they saw the other's changes.