The milking centers

Keith obety finally reached his 18th birthday and was required to report to his local milking center for sperm donation and testing. His mom drove him and dropped him off at the front door, once inside he noticed the waiting room filled with several young 18 year old looking guys like himself and a few a little older, after signing in at the front desk he was told to wait.
Watching fellow boy after boy being called back by a male or female nurse, some of the older looking guys had larger bulges in their pants that Keith assumed were chastity belts and the males were repeat visitors. After about 30 minutes it was his turn as a male nurse called his name, he followed the nurse back to an exam room hearing moans, grunts, squeals, screams, and crying as he passed about 15 other closed doors all accompanied by a pulsating pumping and humming noise and the whole placed smelled to Keith like the scent of his sweaty jockstrap after baseball practice and a more powerful odor of his room after he jerked off and shot his cum.

Once in the exam room the nurse closed the door causing sounds to become greatly muffled and instructed Keith to undress completely. The boy reluctantly complied and removed everything down to his jockstrap, he was slightly aroused oddly from the scent, sounds, and knowing he would be brought to orgasm just like he suspected the other boys in the rooms he passed were, this caused him to pause with apprehension and bashfully blush since nobody had seen him naked since his family doctor for his high school and sports physical.
The nurse noticeably cleared his throat and tapped his pen on the clipboard pressuring the young man to finally slip his hands under his wasteland and pulling his jockstrap down around his ankles pulling it off and placing it with the rest of his cloths, then trying to place his hands in front of his dick that was still becoming more aroused, causing the nurse to tell him to keep his hands at his sides and step on the scale.
After his weight and height were taken the nurse told him to sit in the odd exam chair that was in the center of the room surrounded by a few cabinets and weird contraptions.

Keith was very young looking, he had a very small frame and very thin only weighing 110lbs at 5 feet 8 inches tall, he had semi long brown hair and very pail skin with no chest hair but a thicker brown bush around his penis and no hairs on his balls. His dick was a little more than half hard as he sat back in the chair as the nurse placed his feet in stirrups spreading his legs exposing his penis and balls even more, the nurse told Keith to scoot so down until his bottom was slightly hanging over the chairs lip exposing his pale bubble but and taint even more. The nurse put on a pair of gloves and grabbed a few tools, measuring tape, orchidometer, lube, leather restraints, and lastly his clipboard placing the items upon a table next to the boy.
The nurse told Keith he would need to be restrained for the exam and extraction as he strapped the boys wrist and upper arms to the arm rests, his upper chest and thin waist to the chair, lastly his upper thighs, knees, and ankles to the stirrups. Keith was not going to be going anywhere or really moving his body with the many and tight straps, the nurse then wheeled a stool between his legs, gripping the boys scrotum in one hand and orchidometer in the other he measured each testical saying out loud 18-19ml while jotting it down on the clipboard. This caused Keith to become almost fully aroused, his foreskin slightly pulled back exposing the very tip of its pink head.

Next the nurse had the measuring tape in one hand and as Keith suspected his penis moments later as the nurse gripped his shaft pulling the foreskin back and examining the penis head, then began to pump the boys penis slowly back and forth causing Keith to reach maximum hardness in seconds and a few drops of precum dripping out of the tip as Keith moaned softly very embarrassed like all other guys but wanting the nurse to continue until they shot since they were not allowed to ejaculate for the past 3-5 days under the warning if they did that they would somehow be punished. The nurse stopped once he was fully erect though and then placed the tip of the tap against the boys pubic mound stretching it all the way to the tip then wrapping the flexible measuring table around the shaft at its biggest part he then said out loud as he wrote down the length as 5.4 inches and girth as 3.7 inches. Keith knew he was a little small and hoped he would still grow, he was a bit shorter than average and had a thin pencil dick but his balls were pretty large and they always hung lower making them look even bigger, he knew all this already from looking up boys his age on the internet as well as science journals of average size then measuring himself, he didn't care right now as he only wanted the nurse to resume jerking him off to collect the sample he suspected/figured that was how it was done, little did he know he would soon be on the first insanely pleasurable and painful ride of his lifetime as the nurse grabbed a long silver looking tube from a drawer and the lubricant returning between Keiths legs.

Keith became excited figuring he was finally gonna shoot his 4 day brewing wad as the nursed poured lube onto their hand and Keith rested his head back, his eyes quickly shot open and his head jolted upward looking between his legs as he felt a cold wet finger slip between his butt cheeks and quickly press against then enter his virgin straight hole. Keiths mouth opened up making some noises but unable to form words, only gasps and grunts came out as the nurses practiced finger quickly found the boys prostate and began to rub his finger in circles against it making Keith loudly moan since he never felt anything like this before. His penis pulsed and dribbled out more precum as something inside his bum was manipulated making him feel amazing. Sadly the sensation quickly ended as the nurses slim finger withdrew and then Keiths eyes flashed open again as something even colder and wet was slipped back inside him, looking down he noticed it was the metal tube that turned out to be a vibrating and e-stim probe, it was quickly in position and felt good to the lad but not as good as the moving finger.
Thankfully the nurse was very skilled at this and their finger was thin as well as the probe, as they attached wires to the end of the probe that connected to a console with a tablet on the table next to the exam chair.

Unknown at the time to Keith, the probe itself could actually induce orgasms if need be via electric shock forcing his prostate and seminal vessels to contract forcing an ejaculation at higher settings. Under low settings and with the vibrator in its tip it could cause Keith intense pleasure while measuring and detecting the 18 year olds orgasm since every males sphincter contracts and rhythmically pulsates before they shoot leading to strong and faster pulsations of their anal mussels.