Back in the 70s, my aunt was recently divorced and looking to find an apartment for her and her young daughter.
She was checking out a brand-new upscale apartment complex with a lot of amenities. She wanted to make a good impression, so she was wearing a nice dress and heels.
She got to the apartment a little bit early for her appointment to see a unit, so the sales representative suggested that she take a look around the property. My aunt walked into the state-of-the-art workout room which had a wall of mirrors and the following equipment:
Those "exercise" belts were all the rage back in the 70s and my aunt could not wait to try one out. So, she got on the machine, put the belt around her, faced the mirror, and turned it on.
A few minutes later, a tour group came through the workout room with the sales rep. Some people in the group looked at her in horror, others averted their eyes. She was pretty embarrassed, of course, because here she was all dressed up and shaking away on the exercise equipment.
The sales rep quickly escorted the group out of the room. It was only then that my aunt looked in the mirror and realized that the machine had shaken her underpants down around her ankles.