Please understand I'm approaching this question broadly, not just current "feelz" but also from the ancient environment of evolutionary adaptation times, clear through human history as twisted and sordid as it is.

It's a trope in movies, like Clerks, where her n-count went from 3 to 33 when counting oral sex.

It's in my past as well. A married woman seduced my wife at the time and I. Her deal with her husband allowed her lesbian sex, which apparently included blowjobs.

Thinking about it, getting oral is intimate as hell, at least to me, especially if it goes all the way. Perhaps that's part of why I and many other men really don't get this. How can you do.......that......and it not be intimate as hell?

Going out on a limb.....I could see a few reasons why a willingness to do oral for men who don't qualify for PIV. Birth control would be one, it could possibly defuse some dangerous situations (rape avoidance-a horrible thought but likely effective technique) as well as produce positive situations (prostitution lite- think doing the landlord a favor).

Could it be that there's an evolutionary loophole here that allows women to have oral sex with men they wouldn't have PIV sex with? Is it really cultural? It has to be both, to be sure, but this one has always confused me a bit.