Mr. Peepers (1971)

Sinopsis

Our hero, a nerdy country bumpkin had plenty of experience peeping on animals doing their thing, but now that he has moved to the city he gets to spy on humans. His job as a delivery man means that he gets to pass a lot of windows, and in each one a new voyeuristic surprise awaits. In the end two lesbians catch him looking and invite him to join in on the action.