“I lived in a 2-story house, which was quite old. It had piped steam heating, and one of the issues was that when the heat came on, the pipes expanded(?), causing a weird knocking sound, as if someone was walking in high heels. My bedroom was in the lower floor, and the living room (and entrance) above.
One night I had a girl that I had recently met over and it was her first time at my place. It was late, we were getting frisky, then started doing it. She was on top, riding away. I was having a good time, to say the least. Unbeknownst to me, the heat had come on. So suddenly the knocking starts, and she gets this horrified look on her face, hastily gets up and starts getting dressed. I was so used to the knocking that it didn’t even register anymore.
So I’m like, “what happened? What did I do??”
And she replied, “Your wife is here! I heard her walk in upstairs!!”
And I’m like.. what wife? I live alone!
Soon it dawned on me what had happened, and we both had a good laugh.” – ispeakdatruf