Walter Boos – Schluesselloch-Report AKA The Intimate Teenagers (1973)
Another one in the series of 70’s popular German erotic Reports movies. After Schulmadchen and Tanzstunden Report, this is Schlüsselloch-Report.
This one is a collection of stories recounting incidents to be seen through keyholes.
Audio is German, unfortunately no English subs, but I think you’ll somehow manage to go through this without the subtitles.