The movie was filmed between October 1979 and June 1981. The scenes were shot in the same chronological order in which they appear in the film.
When Nils Malmros called Gitte Iben Andersen and told her that she had become the chosen one to play Lene, she noticed that there was also a nudity scene. She was therefore refusing - but nevertheless said yes, when the film director added in a slight way that all other girls had said yes - without knowing that he had used the same trick towards the other girls.
For the casting, a young Nils Malmros visited all the schools in Aarhus to look at 1400 children. He chose the ones who looked like the kids Malmros had been surrounded by in his second grade. His old class had materialized in a new form with seventeen look-alikes.
In the scene where a lady who cooks for the children on a trip lets different things go around under the table and then they have to take turns feeling it, Nils Malmros wanted a kind of climax where the children would really be surprised and howl. He just didn't quite know what to send around to achieve this effect. Someone on the film crew had found a dead mole and they immediately decided it had to be it. Nils got his desired reactions, and they were later on the editing table cut together with the sausage, which in the film is the last thing that is passed around.