In the window of a book shop. I was working there part time, was closing the shop at about 6pm. A pretty university student who was a regular customer was hanging around. Invited her to stay for a glass of wine. Pulled down the main shutters over the door, but forgot the one over the window. We had sex with her bent over a book shelf. Later that evening a friend called and said he'd been walking past, in the busy city centre shopping street. About a dozen people were watching.