Movie description: "Classmates run a sex experiment". Lina Sun and her classmate spend the day studying together. They sit next to each other, sometimes helping each other, and sometimes trying to peep into each other’s notebooks to check the answers. Everything is calm and quiet. Suddenly, Lina Sun drops a pen. She could just get up and walk around the table to pick it up, but she lies down on the table and tries to grab the pen. Sure, she fails to do so, but she shows her juicy pussy to her curious classmate. They put away the notebooks and spend their precious time in a spicier way.