oral-problem-sex

"What is oral sex?" she asked her friend. His throat wobbled in a swallowing motion due to extreme embarrassment.
He replied, "When a girl sucks a guy's private parts it is called oral sex."
"Have you gone crazy? Why would any girl do that?" she retorted.

Not satisfied she asked her girl friend. She replied, "Kissing is oral sex," and wondered how this girl did not know about as simple a thing as smooching.

This is a dialogue happening between kids of the same class. Age 12 years. At 21 years age or even grown up adults, men as well as women, have problem with the word 'oral sex'. Anyway, what is oral sex?
Here is the beginning of my post.

Some people do call smooching as oral sex. Like, "Our friendship is limited to touching and oral sex,[meaning kissing] I have to confirm what they mean.
For 98% of people 'oral sex' means
female sexually stimulating genitals of a males, as well as the counterpart
male sexually stimulating female genitals. In gay and lesbian community it would involve each others genitals.

We shall see medical aspect of it, and then socio cultural aspect too. You may see a diagram licensed under Commons here. It was created by Francesco Hayez on May 03, 2006
[650 × 454 pixel, file size: 32 KB, MIME type: image/jpeg)]

Commons is a freely licensed media file repository.