Verbal diarrhea not withstanding, the Korean kids I've come to know are a very modest type.
Certainly not in regards to dung jokes, and even less so regarding their character and ambitions, but the impulse as I've seen it, is to immediately cover any measure of exposed flesh with pencil-rendered clothes.
Today for example, I was teaching a class of five 10-year-old girls. We were using a textbook called "Very Easy Reading" and the reading in question was a story about taking a bath. It was accompanied by an illustration of a boy in a bath tub, with his legs and chest sticking out from the bubbles. It wasn't especially racy, but as I was writing on the board and the girls all opened to the page, there was quite a squealing. As I turned around, every one of the five was drawing shorts, a t-shirt, or even a complete black diving suit over the offending nude skin.
It was very funny.
Kids will be kids anywhere you go, and most of them find kissing gross and giggle at the word "panties."
There is however a certain Confucian element to the bashfulness in Korea regarding anything even remotely sexualized.
I was showing an episode of Freakazoid to the early class, and when it reached a scene involving a kissing booth Minwoo recoiled in shock and averted his eyes.
"Oh no! Teacher, this is age 18 plus!"
Paul on the other hand has repeatedly made me pinky-swear that I will invite him to my future wedding, so he can see my wife and I kiss, and then said it will be "very niiiice" with a Borat-type inflection.
Paul however is hardly typical.
A Canadian writer teaches English and finds out what it's like to be a foreigner.