Peggy is chosen to teach a Sex Ed class
Bobby returns home from school with a permission slip. Hank explodes with anger when he realizes the school is seeking permission to send his son to a Sex Ed class. He and Peggy agree that "the birds and the bees" should be taught at home. But Hank quickly nominates Peggy, who was recently voted Substitute Teacher of the Year, to do the honors. With great trepidation, Peggy approaches her son and broaches the subject of sex. When Bobby mentions the word "penis," Peggy goes blank and leaves the room. Left with little choice, Hank decides he will teach his son the same way his own father instructed him: by watching animals mate at a local dairy farm. But Hank is horrified to realize that, through a miracle of modern technology, cows are inseminated by machine. Hank and Peggy have a change of heart and decide the topic is best left in the hands of professionals. But when the high school's Sex Ed teacher resigns after Hank's friend Dale phones in an anonymous death threat, Peggy is drafted to teach the class.
Peggy prepares for the job by reading a variety of books on the subject. Word of her new position spreads quickly, and the entire family becomes the target of derogatory remarks. The perceived "dirtiness" of Peggy's task even affects her love life, as Hank recoils after she suggests they have sex. While preparing for the class, Peggy musters the courage to blurt out the word "vagina." Fed up, Hank tells his wife he will not sign the permission slip (which requires both parent's signatures)
Hank takes Bobby to work with him on the day his wife is scheduled to teach the Sex Ed class. While discussing the touchy subject matter with his son, Hank defends Peggy's use of words describing the human anatomy and suddenly realizes how courageous his wife truly is. He brings Bobby to school and allows him to attend the Sex Ed class. Meanwhile, Peggy, nervous and tentative, enters the classroom and addresses the students.