Get this: the rough translation of the special attack is "dung needle."
There is a similar act in Japan known as Kancho—great explanation here.
Here's a bit from the Korean Wikipedia entry! (interestingly somewhat-translated via Google):
"Iran together into one index finger of both hands ttongchim seunhu, anus of another person with the aim of stabbing one of the children's fun. Chojunggogyosaengdeung primarily, the underage students are often among his age group enjoy the kind of a joke.
Usually done as a joke, or is not ttongchim evil, just like any business, you can be that much violence is in excess."
It goes on to describe (I think) the medical dangers of overzealous ddongchiming.
Wary like this family wasn't...
[Don't be ddongchim evil.]