As has already been pointed out, the word “forced” in the original post is a strong word. It conjures up images of prisoners of war, held captive (naked) in a Vietnamese prison camp, or a suspected drug smuggler being subjected to a strip search, or a Singapore criminal being caned. For the purposes of this post, I think the word “mandatory” might be more appropriate?
Children are subjected to mandatory nudity quite often, because when parents take off your clothes (at a very young age), or tell you to take off your clothes (when you're old enough to do it for yourself), it isn't really optional. Also, children are expected to obey the instructions of other adults with the authority to tell them to strip (doctors/nurses, coaches, etc). Even as adults, there are times when getting naked is basically mandatory (medical exams/procedures, military service, etc).
When I was boy, born and raised in the southwestern U.S., in a very rural/agricultural ranching community, what I would call “wholesome nudity" was not even as taboo as it is today. Today, nudity in the form of soft-core and hard-core porn, is rampant. In fact, almost everything about nudity is now-a-days pornographic/sexual (at a time when pornography and sexuality is rampant). It is very ironic (but not necessarily coincidental) that, when/where I grew up, our culture was BOTH far less prudish regarding “wholesome nudity”, AND simultaneously far more modest regarding pornographic sexuality/nudity.
From a young age, here are some examples of times when it was mandatory for me to be naked in front of others…
1> Obviously, mom and dad (and sometimes others) would bathe me and dress/undress me at a very young age (I certainly was not able to change my own diaper).
2> I lived in a small ranch house, with only one bathroom, with my parents and two sisters (one older & one younger). We all had to shower every morning, and sometimes in the afternoons/evenings (after completing ranching chores, after mowing the lawn, after arriving home from a Little League game, etc). It was simply NOT practical for members of our family to be modest regarding nudity. When we were younger, the children would sometimes shower together (it was sometimes my older sister's responsibility to make sure that I showered properly – and, years later, sometimes my responsibility to make sure that my younger sister showered properly). Our shower had a clear glass sliding door, but even when we were all teenagers, I would not hesitate to walk into the bathroom to brush my teeth while one of my sisters was showering, and vice-versa. I remember on one occasion, when my older sister was approximately 16.y.o. and I was about 14.y.o., I was showering and she was in such a hurry that she jumped into the shower with me... she started shampooing her hair, and instinctively ordered me to start washing her body… and, she helped me also (when we were younger, we would often help wash each other when we showered together, so we didn't consider it to be unusual, even though we were older at that point). By the time she was 16.y.o., she was becoming a very attractive young woman, and I am not even ashamed to admit that washing her body was sort of exciting… and, many years later, we talked about it and she admitted that she had found it exciting also, because I had an erection (I already knew that – her arousal was also pretty obvious at the time). Does this mean that there was EVER any chance of us doing anything more sexual than experiencing this unintentional arousal while showering together? OF COURSE NOT – we were not romantically attracted to each other! I know that my dad saw her naked when she was a teenager. And, I'm sure he must have noticed that she was developing an attractive body. But, would he ever want to DO anything sexual with her? OF COURSE NOT – he was not romantically attracted to her! Wholesome nudity does not mean that we don't notice an attractive body (even the body of an attractive family member), but we have the self-discipline/self-control to admire that body, and even endure a degree of unintentional physical arousal, without allowing the situation to get out of control (how could I not become physically aroused at 14.y.o., while washing my sister's teenaged breasts, seeing/feeling her nipples become very hard/erect, and noticing her breathing get heavy as her body stiffened, while she was thrusting her breasts forward and “washing” my hard penis?). Experiencing some “wholesome nudity” as a child is actually a healthy way to learn that, while nudity does not necessarily have to be erotic/sexual/romantic, it us still possible for spontaneous/unintentional physical arousal to happen, under certain circumstances (or, especially with teenaged boys, for no apparent reason at all), and simply needs to be managed (self-control/self-discipline). Our family certainly didn't go out of our way to see each other naked, but in a small house it was simply inevitable, so we didn't waste any time trying to prevent/avoid it. My mom/sisters saw my dad and me naked (including erections sometimes), and vice-versa. There is almost always a small amount of sexual tension when human beings are nude together (even family members). Somewhere along the line, most parents stopped allowing enough “wholesome nudity”, such that children learn that humans can be nude together, but have self-control over that tension.
3> Proper spankings were a traditional form of family discipline, and the recipient of such punishments was always spanked on his/her bare bottom, and was frequently totally nude. If I got into some sort of trouble with one (or both) of my sisters, we were usually spanked together, into our teens. And, even if only one of us earned a spanking, it was not unusual for others (even extended family and friends) to be in a position to witness such punishments. If I was only naked in front of my father to receive his discipline, I did not become erect, but if females (mother, sisters, cousins, etc) were there, I would usually have an erection.
4> Nudity, to varying degrees, was obviously mandatory for medical exams/procedures. I remember that my pediatrician's nurse was especially strict regarding stripping for every annual exam and other visits (on one occasion, she had me strip naked because I was there for a sore throat – this pediatrician considered every visit to be an opportunity for at least a cursory physical exam). Even as a teenager my mom always came into the exam room with me, and when this nurse escorted us through the exam room door, her first words (before conducting ANY other business – before I had a chance to sit down or climb onto the exam table), were always, “Okay, strip down to your birthday suit so we can get started." She conducted all the preliminary nurse tasks (weight/height, blood pressure, etc) with me standing, completely naked. It was a small office (only one doctor, one nurse, and two exam rooms) so she pretty tightly controlled the flow of events/traffic in the office. But I remember once, when I was a sophomore in high school, she told me to go down the hall to the bathroom, to collect a urine sample. Just as I started walking back down the hallway (after collecting the sample), a high school girl (I knew her quite well) came out of the other exam room, with her empty urine sample cup. I was naked, but she was wearing a gown (I was never offered a gown). The distance that we had to walk towards each other, before passing each other in the hallway, was about 25-30 feet. She was a very attractive, popular, out-going, tom-boy, ranch-land, rodeo-cowgirl (the country girl that every boy was in love with). She did not hesitate walk SLOWLY and to stare directly at my genitals, and to make sure that I knew that she was checking me out. Given the fact that she was clearly checking me out, I would have been more ashamed to cover up with my free hand (my other hand was carrying my unrine sample) than I was embarrassed to have her see my penis. I had never before (and, have probably never since) become fully rock-hard-erect so quickly. I knew that she was watching it happen, so I just gave up any hope for modesty and also slowed my walk just enough for her to enjoy the show. As we passed by each other, she bent slightly and gave my hard penis one delicious slap/spank with her free hand, and whispered, ”You're a very naughty boy!". I almost had spontaneous orgasm/ejaculation right there in the hallway, just from that one spank (to this day, I still enjoy a good erotic penis spanking!). When I arrived back in my exam room, I was still rock hard, and both the nurse and my mom had knowing smiles on her faces. The nurse said, “Well, that part of your anatomy is functioning properly!”.
5> Discipline was strict at the private Christian schools (elementary, junior high, high school) that I attended (K-12). Parents had to agree, in writing, with the schools' corporal punishment policy. In the elementary grades, spankings were mostly administered by teachers. Being called up to the front of the class, to be given a bare bottom spanking with an elementary paddle was commonplace. Girls were usually offered a degree of modesty by waiting until they were in position (over the teacher's lap, over the teacher's desk, etc) before their skirts were raised and their panties lowered.(just enough in back) to expose their bare butt cheeks. But, boys were almost always required to pull down their pants and underpants to their ankles, and raise their shirt and vest to their arm pits, before assuming the position (an erection often on display). In junior high school and high school, the boys' and girls' PE coaches were the designated disciplinarians. Even if you got into trouble with your math teacher, the librarian, or the cafeteria lady, you would be required to report to the appropriate PE coach when you deserved a paddling. These paddlings were administered inside the boys' and girls' locker rooms (either after your PE class period, or during after school detention), with the naughty boys/girls totally naked and bent over an old-fashioned (out of service) vaulting horse. Erections were not uncommon, because of the embarrassment of having all the other boys watching the naughty boys receiving their punishments.
6> Extracurricular school sports physicals were also administered in the boys' and girls' locker rooms. A doctor and his nurse set up their portable exam table and other equipment in the locker room and all boys/girls who were trying out for an extra curricular team had to get naked, shower, dry off, and then stand in line to be physically examined (assembly line style). Erections often happened when genitals were being so publicly examined.
7> Boys were required to swim in the nude in the school pool, and at the YMCA, and girls often figured out how to sneak peeks. Starting in the junior year, however, coed swimming was a PE elective. When I was a junior, I signed up for this class, along with only one other boy (Kent), and three girls. Because only five students registered for this elective, they almost canceled the class, but we begged the coach assigned to teach this coed class to teach the class anyway. Of course, we all showed up wearing swimsuits. But the girls teased that the coach should make the two boys swim in the nude. Surprisingly, she said it was up to us. For a few more days, Kent and I continued to wear our swimsuits, but the girls kept daring us. So, during the second week of class, we decided to show up nude. The girls (and the female coach) were clearly delighted. About two weeks later, Kent and I teased that the coach should make the girls swim nude also. To our amazement, she gave the same answer… “It's up to them." But, she said it had to be unanimous for the girls. If they ALL agreed to take off their swimsuits, she would allow it. But, if even one was unwilling, then it would not be allowed. The girls immediately/unanimously agreed, and allowed Kent and I to watch them remove their suits on the pool deck, and stand naked before us. The girls, and the coach, enjoyed watching Kent's and my penises stand to attention. During the final week of that class, we (the boys and the girls) dared the coach to take off her swimsuit also. She agreed (she was a young liberal-minded teacher – just out of college – perhaps 23.y.o., with a very attractive/athletic body). She had been born and raised in our community, and had graduated from the Christian high school about 5-6 years prior (she was pretty good friends with my older sister), and returned to teach after attending college. The girls insisted that Kent and I stand on the pool deck while we watched the coach remove her suit, because they wanted to see if we would get hard again (… we did). Just 5-10 years earlier, this coach (when she was still in the junior and senior high schools) had done some babysitting for my parents (watching me and my younger sister when my parents and older sister weren't around), so this coach had seen me naked when I was younger (she had even put me over her lap and spanked me once). So, I felt that their was some sort of karma or justice at play when she stood in front of me and Kent, and removed her swimsuit. Of course, now-a-days, if we (5 coed high school students and a young 23.y.o. female coach) were caught swimming nude together (especially at a Christian school), the coach would almost certainly be fired, and possibly prosecuted for some type of crime! We didn't get caught, but if we had (back then and there), the school superintendent would probably have considered it an example of rebellious behavior that needed to be punished, but probably would have laughed to himself at the silly things that young people do. This young female coach was the daughter of the one of the male PE coaches (he was also the celebrated legendary high school extracurricular football coach – a hero in our community). If we had been caught by him, he probably would have marched all SIX of us directly into either the boys' or girls' locker room and paddled all SIX of us right there and then!… we were already naked, after all.
8> Many boys and girls attended the boys' and girls' summer camps on opposite shores of the reservoir/lake. Many activities at each camp (especially swimming – skinny dipping) were “clothing optional” (which really meant “mandatory” nudity). The boys and the girls would often take unauthorized sightseeing canoe trips past the other camp.
9> When I was in college, I joined a fraternity, and attended on an ROTC scholarship. Both involved mandatory nudity. During pledging, especially during “hell week”, pledges were subjected to various pledging rituals (now-a-days most would be considered illegal hazing), which often involved nudity, and/or nude discipline with a fraternity paddle, in front of other nude pledges, clothed active members, “Little Sisters” pledges (who were sometimes also simultaneously nude, and at risk of receiving the paddle for failing during a pledging ritual), and active “Little Sisters” members. Male and female ROTC cadets started attending various military training programs (including the ROTC equivalent of Army Basic Training) during the summer between their freshman and sophomore years in college. As with all basic military training and entry level military service, there was absolutely NO regard for sexual modesty. This was before females were allowed to be “fully integrated” with males in the military, but there were still situations where certain females were present during times of male cadets' mandatory nudity. But, the reverse was not the case – a great deal of effort was put forth to protect the female cadets/soldiers from being exposed (nude) to males.