On a recent Saturday, Amy Albright was celebrating her bachelorette party on West 14th Street. A table was filled with miniature cupcakes and glasses of pink Champagne. Nancy Sinatra’s “These Boots Are Made for Walkin’ ” played on the stereo. A shirtless waiter took coats. The guests, mostly in their 30s, sat down, waiting for the main attraction: a nude male model.