When I was 17, a girl invited me over to talk over coffee. I had no interest in her other than as a friend at our high school, and I was acquainted with her boyfriend. So we were chatting over coffee in her kitchen, while her younger 10-year-old sister watched TV in the living room. Gal in the kitchen ambushed me with "affection", drags me to the couch and chases her younger sister off to her room. And shortly after, this gal drags me to her bedroom and strips. I protested the whole time. So we hear a car drive up, and she yells at me "it's my parents, get out now through the back door!". I hopped the backyard fence and left. If her father found me in her bedroom, I could've ended up like the boy in that story!
Anyway, later on I told a friend what happened. His eyes went wide, told me the same thing happened with him recently, and to a couple other guys we know, involving the same gal. The gal's boyfriend never knew what she was doing behind his back.
Her parents must have had amazing intuition to keep showing up at the right time like that. :-)