Since I love the idea of mandatory exams, especially when done in a group, this topic has really sparked some ideas for me. I can see myself even doing a full-length story on this theme in the future. Maybe.
But for now, here's my initial take on how this might be done.
It's assumed that the citizens live in a totalitarian country that centrally directs and controls most aspects of their lives. The exam would take place at a government run facility. What I had in mind is something very similar to a military processing center where recruits are examined and processed. All male and female citizens would receive an official notice 30 days prior to turning 18 informing them of the date and location when they are ordered to report for mandatory processing. In this country, all citizens are required to spend several years serving their country in some way. The purpose of this exam is to determine how the young citizens will do that. They will either be chosen to continue their education in a school of higher learning so they could later serve in some professional capacity, or serve in the country's military, or be assigned as a common laborer in a government sponsored job. After 4 years of mandatory service, the citizens are free to pursue their own careers.
The processing itself includes a physical exam, mental, psychological and aptitude tests and physical fitness tests. Their long day begins with the young citizens, both male and female at the same time, arriving very early at the processing center. After verifying their identity and completing a large amount of paperwork and written tests, the citizens are escorted to a large reception room where they are ordered to undress. Males must undress to their briefs or boxers and females down to their bra and panties. All of their clothing and other personal items are put into individual containers and safely locked away. In return, the citizens are simply given a tag with a bar code that they are to hang around their neck to identify them. Having likely heard stories about this processing from their friends and siblings, the citizens already know that the underwear that they are now wearing is the most that they will be allowed to wear for the remainder of the day. In fact, they are likely well aware that many parts of the processing will take place in a state of full nudity and in open view of other citizens their same age, both male and female.
Now that they are undressed, the citizens are moved to another holding room and randomly separated into groups of 8. Most of the groups have an even number of male and female citizens. Each group of 8 citizens will be examined and processed together for the entire day, moving from room to room within the facility for the various parts of the exam. Now that they have been assigned to a group, the young citizens likely take a moment to look at the others in their group. They know that throughout the day they will have plenty of opportunities to see these strangers without any clothing at all. And more importantly, they begin to feel embarrassed and apprehensive about baring their own body to this group.
The group is first escorted to a room where blood is drawn from each citizen. A urine specimen is also obtained at this time. The collection of urine is done as a group, with all members able to observe the others. Underwear (except for bras for the females) is removed completely prior to collection of the specimen to ensure that no tampering takes place.
After putting their underwear back on, the group is now taken down the hallway to a large examination room that is staffed by 2 or 3 doctors and a couple of nurses. The medical personnel and other examiners that they will meet throughout the day are a random mix of male and female. The exams now commence, with the doctors and nurses performing parts of the exam on several young citizens at the same time. They begin simply enough, checking HEENT, BP, pulse, respiration, heart, lungs, abdominal exam, etc. In this room the citizens receive the least invasive parts of the exam that are performed without them removing any of their remaining clothing.
After all 8 citizens in the group have been examined, they are escorted to the next room that is staffed with a different set of doctors and nurses. In this room they each receive an EKG and have height and weight as well as skin fold measurements taken. Then it's on to the next room with another set of doctors. They end up moving like this several more times, with each room covering a different specialized area of the exam. One room might conduct extensive orthopedic exams, while another room does a neurological exam.
Of course there's one room that conducts genital and rectal exams. Just like all of the other parts of the exam, this exam is conducted in full view of the other citizens. The male citizens are all examined first, followed by the females. One at a time, each male citizen is commanded to step to the middle of the room, remove his underwear and spread his legs apart. A doctor then sits in front of the male and performs a thorough examination of his testicles and penis. A hernia exam is also included. He is now instructed to bend over and reach for the floor, keeping his legs parted. The doctor examines him for hemorrhoids and does a basic digital rectal and prostate exam. As the doctor prepares to examine the next citizen, a nurse takes measurements of the first male's genitals, recording his penis length and girth as well as using an orchidometer on his testicles to gauge his physical maturity level.
The females are first examined while standing in front of the doctor, just as the males were. Following that they are instructed to climb onto an exam table and place their feet into stirrups for a basic gynecological exam. While in the stirrups, they also receive a basic rectal exam. All this takes place in full view of the others in the group.
Once again they are allowed to put their underwear back on when moving to the next room. But it doesn't stay on for long since the next room is where each citizen receives a much more thorough rectal exam using an anoscope. All 8 citizens are ordered to remove their underwear and are each given a quick rectal exam by a nurse. This exam is used to determine if a citizen requires an enema prior to the actual rectal exam. Those that are not clean enough to be examined are now given an enema while the others commence with their exam. The exam itself involves each citizen climbing onto an exam table and being positioned on their hands and knees. A well-lubricated anoscope is then inserted into their rectum to allow direct viewing.
The medical exams are now complete and the 8 citizens move on to the fitness testing phase. They are taken to a large room and ordered to strip completely. This is done to avoid leaving them in sweaty underwear during the remainder of the day. At the discretion of the examiners, well-endowed males may be provided with a jockstrap to wear during some of the more strenuous parts of the testing. Likewise, large-breasted females may be provided with a sports bra to wear. But it is expected that most citizens will perform the exercises in the nude. The citizens now form a circle facing each other and begin a series of exercises on command. The exercises include running in place, jumping jacks, bending and squatting exercises, push-ups, dead lifts, etc. The purpose is to test their strength, stamina and agility.
Psychological and sexual response testing is next. One by one the citizens are taken alone to a private room while the others wait together in a holding room. This private room has 3 or 4 questioners that are seated at one end of the room. The citizen is ordered to remove all remaining clothing and to stand with their legs widely separated and their arms above their head. An assistant fastens their ankles and wrists to spreader bars that are at their feet and above their head respectively, so that they are now in a spread-eagle position, fully nude, and standing before the panel of questioners. The nudity and restraints are a technique that is deliberately designed to increase the apprehension and stress level of the citizen to see how they react in uncomfortable situations.
A video now begins playing in direct view of the citizen showing various acts of violence: mobs, beatings, shootings, stabbings, acts of torture, etc. Questioning from the panel now begins, posing a series of questions designed to gauge their response. If you think of the scenes in Blade Runner where replicants are questioned, you'll get the general idea.
After a few minutes, the video now changes to sexual scenes. First men having vaginal intercourse with women, women performing oral sex on men, men going down on women, etc. The questioning also turns to sexual topics, trying to determine the citizens sexual history and sexual preferences. Intimate details of their sex life are discussed. The video now changes to women having sex with other women as the questioning continues. It changes again to show young men fondling each other in a group shower and graphic video of men having sex with other men, including oral and rough anal sex. Finally, as the questioning continues, the video shows a restrained man being penetrated anally by a woman with a strap-on. Throughout the interrogation, the questioners in the room are looking for signs that the citizen is becoming aroused. Depending on the results, the questioners are allowed to touch and grope the citizen. For males this includes making physical contact with their penis, testicles and buttocks. For females, their vagina, breasts and buttocks may be touched. At their discretion, the questioners are permitted to anally penetrate males with a dildo to gauge their response to being forcibly penetrated. Females may be penetrated anally or vaginally. All of this takes place while the citizen is still restrained and helpless to resist.
Once all 8 members of the group have completed their individual testing and are together again, they are told to form a circle facing each other. They are all still completely nude. They are now ordered to bring themselves to orgasm by masturbation. The males are given a plastic specimen cup and told that they need to capture a sample of their ejaculate. Lubricant is provided for those that require it.
All citizens are now permitted to put their underwear back on (and for females their bra) while they wait in a large holding area with other groups. During this waiting period, final reports on each citizen are being prepared prior to their audience with the service committee.
The group of 8 is now taken together into another room to face the service committee. All 8 citizens line up at the back of the room and are allowed to silently observe as each member faces the committee alone. They are all still wearing just their underwear. Across from them at the opposite side of the room is a long table with 7 men and women who are seated, much like a draft board. The first citizen is called forward and ordered to stand just a few feet in front of the committee. They are instructed to remove all of their remaining clothing and to respectfully stand at attention. Their hands must remain at their sides, and any attempt to cover their privates is forbidden. The committee now begins to review the reports for this citizen, addressing them if necessary to clarify anything in the reports. At their discretion, individual committee members may ask the citizen to move, turn around or change position so their entire body can be visually inspected. Most typically males are asked to spread their legs apart and to lift their genitals for better viewing. If not circumcised, a male might be asked to pull back his foreskin. Females are typically asked to move their hands behind their head in order to better view their breasts. Both males and females are often asked to turn around and bend over so the committee members can inspect their buttocks and anus. The commands that they are given are deliberately embarrassing in order to determine whether the citizen is willing to faithfully serve their country no matter what is requested of them.
After reviewing the reports and the final visual inspection, the committee makes their decision as to how the citizen will serve their country for the next 4 years. Their decision is binding and final. It cannot be appealed. Each citizen now has 30 days before they must report to their assigned activity.
Once all members of the group have received their decisions, they are marched back as a group to the original reception room where they undressed. This time instead of putting on their underwear first, they are taken to the room still fully nude. This impresses on them that their lives now belong to the state. They are finally allowed to redress and head back home to enjoy their last remaining days of private life.