I was once dating two girls at the same time, they were friends and lived across the street from each other. They both knew I was dating, and sleeping with, the other one so it was fairly normal for me to spend the night at ones house, wake up and cross the street to the other ones. Fairly often I'd cross the street to find breakfast waiting for me when I got there. They would both look for my car at the other ones place and if it was there they knew I'd likely be over at some point the next morning.

That went on for a couple of years.