This happened one time when my I was in my early 20s and I babysat for my older sister Ella. I was unmarried at the time, while Ella and her husband Rob had one daughter, six-year-old Keisha.
Ella had to go away on a business trip overnight and Rob was in the armed forces, so she asked whether I could come over and look after Keisha for 24 hours. Accompanying me was my long-term boyfriend (and future husband) Marcel.