Weird trivia about this film...

Roth originally wanted Cerina Vincent to show her naked buttocks during her sex scene with Rider Strong. Vincent, who had previously played a nude foreign exchange student in Not Another Teen Movie was afraid that exposing too much of herself would lead to being typecast as a nudity actress and vehemently refused to bare her buttocks. At the peak of this stand-off between actress and director, Vincent told Roth that if he wanted the shot so badly, he would need to re-cast the role of Marcy with another actress. But they managed to reach a compromise - Cerina would bare one inch of her buttocks on camera, no more, no less. Eli Roth brought a ruler along to the filming and measured Cerina's buttocks, to be sure he got his one inch. Bedsheets were then taped to Vincent's backside at the designated level and the scene was filmed. Only the second (behind-the-back) shot features this one inch, in the first (over-the-shoulder) shot, the bedsheets cover Cerina's buttocks completely.