flash
in. to display one's private parts briefly. (Use caution with the topic.)The guy flashed and moved on down the street.She flashed briefly, providing the show that people came to see, and left the stage.
flasher
n. a man who exhibits his genitals.The cops caught the flasher and took him away.Sarah said she thought she saw a flasher in the library.
free show
n. a peek at a private part of someone's body, usually a woman's.Martin looked like the type who was always waiting for a free show that was never to be.A true gentleman takes no notice of a “free show.”