[F] Changing room exposure!

so my wife and I went shopping, for those of you in the UK we went to Bluewater and House of Fraser, my wife picked a dress which had a zip at the back all the way down the dress, we went to the ground floor which is for men, we both went in to the changing rooms which are separate cubicles and she put the dress on, i went to the next cubicle and watched, She took off all her underwear and was just wearing the dress, she waiting for a guy to come into the changing rooms and stepped out, she told the guy her zip was stuck and could he help, he unzipped the dress in the middle of the changing rooms and she let the dress fall to the floor showing her naked body, she pretended to be embarrassed and picked up the dress showing all her naked curves to the stranger and ran in to her cubicle, I waited a few minutes then joined her and we had fantastic sex!!