Re: erections sans any known sexual stimulation ... does it happen? It does (and I can safely say that as a male with the equipment to prove it). Oookay, in case it's confession time, I'll speculate that my most common erections happen when I'm asleep as a sort of mechanism to stave off having to urinate. That way I can sleep more, and get up for pit stops less (hopefully/in theory). Sort of like "hibernation for the bladder."
Plus I used to be a lot younger (it's true), and when I was, well for instance it was a rather embarrassing inconvenience for me as a teen in school to often get an erection for no conceivable reason. Just my equipment's way of getting practice/exercise?
And sure, back in those days, the "dreaded" morning erection was a normal occurrence, as were "wet dreams" that had no "brain-conjured wet dream content" ... my apologies if that was way too much information.
I basically know nothing about whatever mechanisms females have for "holding it in." I do know (interesting fact), that all babies start out in the womb as, well, girls. The "kids with the testosterone" have genitalia that morph during the pregnancy intil they have out-and-out male equipment.
So does the penis have multiple functions? Sure. Not as many as a jet fighter, but certainly enough to make it more than just a sexual organ.
"Just because sex is the most popular thing in this country of the U.S.A. doesn't make the parts of ourselves that takes part in sex biologically function exclusively for that purpose."
I think I get that? Qualifier: Would a study be useful to find out how popular sex is in other countries? Sex is, after all, pretty popular throughout the animal kingdom. Something about reproduction? Breathing, drinking, eating, and finding shelter (elements of immediate survival) do trump sex (the element of long-term species survival) though.
As an American, I just find it impossible to imagine how anything could be better than sex.
Re: circumcision ... oh boy, here I go, committing heresy by not calling circumcision child abuse and lots of other bad things. I've done some reading on the subject both pro and con, and I guess I'm technically neutral on the subject. As per Wikipedia, scientists are still speculating about what the foreskin does for us. Not saying those scientists are talking out of their asses, just saying there's a lot of unknowns about that part of the body.
Personal note (I know you'll all be looking forward to this): I seem to be "getting my foreskin back" in my "relatively old age," and I'm not sure how I feel about that. Sometimes when I'm drying off out of the shower, I observe that, "Oh look, the turtle is retreating back into its shell. What's it so timid about? embarrassed about being spotted in the mirror?" "I must hide," says the turtle. "If I cannot see you, then you cannot see me. I am hidden." I don't think I'm ashamed of it, but it seems a little silly (to me)? Certainly isn't what I'm used to seeing. (Dear readers: I beg you to not be offended by my levity. It's how I cope with talking about my privates. Easy for some people to do, not so easy for me to do.)