The shuttle bus lurched to a halt kicking up a dusty haze from the heat scorched earth beneath it's tires. It's occupants were a group of young girls on a field trip hosted by the local veterinary organization for those interested in applying as assistants in the county's medical outreach program. The county of Forest nestled in the state of Nebraska was so spread out that farmers were on a waiting list for the local vets to visit to provide the routine inoculations and medical checkups of their animals.

The outreach program was designed to train potential assistants in helping to provide the basic services of health care for the animals that the veterinarians couldn't attend to in a timely fashion. Jen and Heather had both just graduated college and were excited at the prospect of starting a new career working as vet assistants.

The girls broke up into three groups, each paired up in teams to work together with one of the local vets in giving a series of injections and taking blood samples from the horses on the Cooper Ranch. Jen and Heather were working with Dr. Susan Blake this afternoon. As the trio headed off to one of the barns the other girls in the group spread out to go about their own tasks with their respective vets.

Jen and Heather chatted with Dr. Blake as they entered the stuffy barn, the air was dry and dusty, filled with the smell of fresh hay, dried leather and the unmistakable scent of horse urine and feces. "Geeez it's pretty ripe in here." Giggled Heather. Dr. Blake smiled and spoke softly to the pair telling them they'd better get use to this if they intended on working with horses and other farm livestock.

Jen turned to her friend and said "Yeah Heather, what did ya expect roses and cherry blossoms?" Dr. Blake just smiled and told the girls to get serious as they had plenty of work ahead of them and some of it might be a bit unpleasant. Dr. Blake led the girls over to one of the stalls that housed a stallion called Thunder. He was jet black in color with a coat as sleek and bright as polished onyx.

"Ok girls let's get to it, this is Thunder and we need to collect both a blood and urine sample from him." "I'm going to show you how to draw the blood but I want you to get one of the plastic cups to catch some of his urine in when he pees." I have rubber gloves in the kit there so you can put those on." Instructed Dr. Blake.

The girls both looked at each other with sheepish grins wondering who would be the one to hold the cup as Dr. Blake began drawing the blood sample. The two girls gloved up and knelt down beneath Thunder gazing in awe at his massive penis. Heather asked Dr. Blake how soon she thought it would be before the horse decided to pee so they could get the sample. Dr. Blake told the girls that it might help to use the cleansing rag in the bucket of water by the stall to wash the animals penis as it should stimulate him enough to capture the sample.

Jen reached over and grabbed the rag and began swabbing the horse's penis with it, wiping it down as it began to grow and unfurl from it's leathery sheath. "Holy shit, he's gettin a boner." Squealed Jen. Girls, girls, that's natural, don't get in a panic." Chided Dr. Blake.

Jen washed the brute's thick shaft with the rag rubbing up the veiny stalk and over the head which spread out like a huge flower. "God Heather, I can actually feel his blood pumping up his cock, the whole thing is like hummin in my hand." Whispered Jen.

Heather leaned in closer to her friend and whispered back "Imagine tryin to suck a cock that damn big, you'd strangle on that thing." Both girls were mesmerized by the girth and length that was jutting out of the animal's sheath. Heather mouthed to her friend hoping that Dr. Blake wouldn't pick up on it and said to Jen. "I dare ya to give that dong a little kiss." "Fucking gross out!!!" Yelped Jen. Both girls began snorting with laughter but came to an abrupt halt when Dr. Blake leaned down and spoke to the pair.

"Go ahead Jen, give it a kiss, hell I've done that and plenty more many times and it's not as bad as you might think." "In fact I bet you'd like it, I know I sure do." Both Heather and Jen were shocked speechless, barely believing what they had just heard. Dr. Susan Blake slid in between the pair and told them to watch and learn. The woman knelt beneath the horse and used both hands to grip his huge stalk, urgently stroking up and down the thick veins running along the sides of it. She told the girls to use their fingertips to press on the veins, to feel the blood coursing thru them as it vibrated with the awesome power of the animal.

As if in a trance both girls began to trace the veiny tubes, feeling them surge with blood and vibrate thru their fingertips. Jen and Heather both gasped at the sensation, the force with which the brutes erection began to grow and throb. "Now cup his balls girls, feel how huge they are, how they begin to swell as his seed builds up in them." Moaned Susan. Shaking with curiosity Jen and Heather began to cup and fondle Thunder's enormous ballsack. The animals balls were huge, the size of baseballs nestled within the slick leathery flesh, hot to the touch as they pulled and rubbed on them.

Heather was getting dizzy from the heat in the barn and the tingling that began to grow in the pit of her tummy spreading down toward her cunt. Jen was lifting Thunder's balls in both hands, feeling them throb as his boiling load began to churn within them. The girls looked to Susan as if pleading for direction only to see her gripping the cock shaft in both hands, her tongue darting deep into the animals piss slit.