A better example might be being able to have one deepthroat from Sasaki Aki or any of your favorite oral experts. Imagine that you only get to have it in a condom. Also a letdown, and considering that oral sex does not cause pregnancy (duh) and has lower risk of infection, even bigger of a letdown... though on the other hand, I personally feel that oral sex is actually more intimate in some regards: after all, you're fucking the person's face. So, basically, pussy is the best for biological and symbolic reasons as being the "flower" etc. etc., anal is the best for being "filthy" and "forbidden", and oral is also "forbidden" but it's possibly the cleanest of the orifices, the most intricate and beautiful one (it's where the speech comes from, the singing, the words of love... and yet you get to stick your penis into it)
And maybe an even better example is if you're obsessed with she-males (I've gone through that phase, so I know): imagine being able to have one go with someone like Dany de Castro, but only in a condom (though you know — since it's a dream, again, — that she has no STDs, so she's just not willing to do it without it). Possibly shemale porn (and maybe gay, though I haven't checked) is much more focused on doing it bareback — again, due to, I think, at least partially, the overall "forbidden-ness" of anal, multiplied by the fact that it's not straight sex (as much as anal can be straight, i.e. that it's between a man and a woman). Man, those guys who had a chance to f...ck her bareback before she had those balloon-like fake tits... those were one of the luckiest guys shemale-dream-fuck-wise... but I'm having my shemale-era flashbacks... I guess you can't really quit shemale porn