Erik Stifler (John White) has a difficult time living up to his family name. He is Steve and Matt Stifler's cousin. He is perhaps the only Stifler about to graduate from high school as a virgin. The film opens with Erik feigning illness so that he can stay home and masturbate. Unfortunately, just as he is about to ejaculate, his parents and grandmother unexpectedly walk into the door and are hit with Erik's semen, after which his grandmother dies of a heart attack. Erik's dad later surmises that, as a Stifler, his son should be out having sex instead of masturbating. Erik's girlfriend of two years, Tracy (Jessy Schram), loves him, but is not ready for intercourse. Tracy decides to have sex, their first attempt goes horribly wrong, and she backs out of trying again.
Erik's friends Cooze (Jake Siegel) and Ryan (Ross Thomas) plan a road trip to visit Erik's cousin Dwight Stifler (Steve Talley) in Michigan during an event known as the Naked Mile. Tracy sees this as an opportunity to give Erik a "guilt free weekend pass," hoping that he can quench his lust and get sex out of his system since she is not ready.
Erik and his friends arrive on campus and witness an over-the-top drinking contest where Dwight is crowned a campus champion, lose a rough game of football against a bitter rival fraternity composed almost entirely of midgets, and end up in a brawl with those same midgets on several occasions. This rivalry comes to a head when the midget fraternity attacks Dwight, landing him in the hospital. Dwight is back in full form later that evening when it is time for the Naked Mile run.
Erik meets a college girl with a fetish for virgin boys and as they steal a kiss, a news crew captures the moment. Watching the news report about the Naked Mile back at home, Tracy is upset and feels guilty that she allowed Erik the free pass. Her friends convince her to also lose her virginity before he gets back. Later that evening Erik realizes that he loves Tracy and rushes back to see his girlfriend. When he gets to her house, Tracy's dad says she is at a party and Erik arrives at the party just as Tracy has headed upstairs, presumably to lose her virginity to her ex-boyfriend. Erik loudly pounds on the closed bedroom door, proclaiming his love for her. However, Tracy was not in the room because she had decided that she could not go through with her plans.
Later that evening, Tracy and Erik decide that they should be each others' first. They make love that night. When Erik returns to the college to pick up his friends the next morning, each boy shares stories of his experiences from the night before. The three friends drive back to East Great Falls.
