Though the onscreen sex stops just this side of hard-core, it's fairly evident that intercourse is actually taking place in some scenes. Production notes assert that Sang Hyun Lee fell in love with his co-star Kim Tae-yeon during filming but that this was not reciprocated.
The film screened version is quite different from the first one. About 15 minutes were deleted from the original version. First of all, most of the scenes revealing Y's identity as a high school student disappeared. It was an arduous measure by the production company to delete the hint of "perverted sexual activity with a minor," which was the decisive reason for the rating suspension. In addition, some lines containing genitalia or vulgarity were removed. A committee member who participated in the deliberation said, "The film has changed a lot. There are no settings to directly reveal that Y is a high school girl. The film was very polished, so I decided it would be okay for people over the age of 18 to watch it."
In the scene where 'Y' is beaten by 'J', director Jang Sun-woo suggested to use a "fake rod" with styrofoam inside, but actress Kim Tae-yeon said it did not look real and asked Sang Hyun Lee, her co-star, to beat her with a real rod.