"Les Petroleuses" with Brigitte Bardot.  

This vintage film is about CFNM forced by a femalewith a gun. At one scene  Bardot interrogates four men, she forces them to strip naked in front of her and rains buckshot on their bare asses! At first completely nude guys do not want to say anything to her. However, after a few shots frightened jump and scream her about the oil.  You can watch four naked, shaking men's butts aand a laughting nice woman. I think You are going to like the scene.