The teacher later apologised and insisted that it was a mistake, blaming the fact that the saucy video got mixed up in her lesson notes.Parents of the teenage students are furious, however, and are demanding answers.Nicolar Tolerson told KARK-TV: "My concern is with him [his son] being in that environment.""She was performing sex acts."He added that the teacher phoned him and "sounded apologetic."Mr Tolerson added: "My heart goes out to not only my son, but other children in the classroom."School officials said they are investigating how the mistake was made, and are looking into how it can be prevented in future.The teacher may yet face disciplinary action.(dailystar.co.uk)ANN.Az