One time years ago, we were driving home from a weeklong camping trip at the ocean and decided to stop at a cheap motel. It was raining, and I didn't feel like setting up the tent in the rain. Six people with a bunch of dirty camping clothes crammed into one small motel room is not very luxurious, but my kids were at the age where they still got excited about vending machines, so this experience was a big treat for them. The three oldest kids slept in one bed, while Spouse, the baby, and I slept in the other bed.
When Spouse and I both woke early, we decided to sneak into the bathroom to have sex while the kids were still sleeping. The bathroom at this particular cheap motel was tiny, so we congratulated ourselves on the acrobatic feat, which we had pulled off without waking the children.
Imagine our surprise, when we emerged from the bathroom and found Daughter, who must have been ten or eleven, sitting up in bed, wide awake, reading a book. She looked over at both of us, gave a smug smile, and said, "I am going to need therapy for THAT some day."