first off, the power dynamics between het and gay exhibitionism are totally different.
within gay subculture, big dicks are fetishized and there is a tradition of showing off. hell, we're the sexual orientation that reduced seduction to a crotch grab and facial expression response.
but gay men generally show off to other gay men who want to be shown off to and most gay men want to be shown off to by hung gay men.
as for all men, there are those who don't know what 'no' means and believe that their penis is the center of the world and time begins and ends with their orgasm with others just objects for their gratification.
but for gay men, many wear revealing compression shorts and such at the gym. there is almost always showing off, jacking and sucking at any gay gym's wet area.
also at gay frequented nude beaches the sexual tension is high. some nudists would try to get men to forget thinking about sex every 10 seconds to totally desexualize the nudist experience. and there are those gay and het men who oversexualize it (see below).
appropriateness of exhibitionism, therefore, is completely contextual. even within the queer realm, the folsom street fair where public nudity and sex are tolerated is not the castro street fair which is pretty clothed.
but for the exhibitionist in me there is nothing more fun than hanging out at the gay nude beach casually sporting a roaring hardon with other like-minded gay men or at a het or mixed beach 'inflated.' sometimes even het couples have taken an interest in my big dick and started to play with each other, with 'sympathetic' boners popping all around.
for an example of a het exhibitionist male see:
rec.nude posting on haulover exhibitionism:
... But three guys in particular made me want to keep relocating my bare
ass down the beach: a bleach blond tattooed middle aged guy, a wildly
long curly haired tan guy, equally middle aged and grossly tattooed;
and a preening bald black stud who specialized in self adoration.
They just couldn't sit still: every youthful single female and
male/female couple was approached. Every syllable of their
conversations was audible within 50 feet. The black dude had the
greatest range. Amazingly, in my three hours there, he managed to
strike up self-referential conversations with at least a dozen
couples, always managing to keep his half-erect cock and gym rat pecs
within worshipping distance of the female he was talking to.
i saw this guy at haulover in n. miami beach last year and it was one of the most mesmerizing things. a het dude with a 9" uncut cock always at half mast at least wandering up and down the beach offering suntan lotion massages to white women. he'd score 2 out of 3 times, and as he massaged the protective ooze into their pasty white flesh, he'd inevitably pop a boner that bobbed up and down with his motion. a so fla videographer friend says he has video of him popping a load.
the first day that i was there, he caught a glimpse of a 50-ish woman's twat and sprang to attention immediately. it was fucking hot.
it is also said that in order to be a good voyeur, one need be a good exhibitionist first.
my take is that i was blessed with a big dick and that i have a certain responsibility to show it off to those who want to see it.
again, the idea is to show off, not to get busted; discretion is the better part of valor.