ledge party
n.— «After the usual alcoholic overindulgence, I followed him upstairs, where I soon passed out on his sofa. There, I assumed the starring role in a garden-variety “ledge party,” my deflowering on display for anyone desiring a peek. Ledge parties, for those of you who didn’t attend party-school universities, featured fraternity boys luring their unsuspecting companions to a lair of choice, where they engineered some semblance of sex for the viewing enjoyment of their voyeuristic brethren, who watched from the window’s ledge. Unlike typical fraternity houses, these were contemporary buildings with plate glass windows and wide ledges that formed perfect viewing platforms.» —“My Sorority Pledge? I Swore Off Sisterhood” by Kelly Valen New York Times Dec. 12, 2007. (source: Double-Tongued Dictionary)
This is totally unacceptable, and while it may happen often enough to have a slang term that makes it sound okay, the usual word for the above scenario is RAPE (with accomplices, in this case). Though the author says others helped her out of the scene, it sounds as though they were a bit late. Such despicable predators need to be told that this is not okay, and stopped. Don’t participate in this, and if you can’t do anything else about it, perhaps it is wise to call the police.