Hot for Teacher(2006)

Original title: 누가 그녀와 잤을까?

Strict teachers, all those hours inside four walls, all your desires and youthful energy repressed. School is an endless drag - until she comes along. Uhm Ji Young has a perfect body and metric tons of sex appeal, and she knows it. Needless to say, all the students go crazy, and the male teachers too! They should be preparing for the annual school festival, but they're all occupied with other matters.