I remember seeing this movie in late 1980s early 1990s. English movie that was dubbed in French. American movie.
2 scenes that I remember
The guy is a virgin and not ready for sex, so he uses a pepperoni instead. The girls freaks out, then later in the film, his friends teases him
The guy and an other girl are in a bed, and they pretend to have sex using a miicrophone plugged to a high powered stereo.
The movie you are thinking of I can almost guarantee is “Meatballs III”
🙂