Many thanks to Darkness Monger, who sent me a link to a movie called "El Apando," which, I think would be in American prison slang, "The Hole." It's about some inmates in a notorious Mexican prison who try to get the women in their lives to smuggle drugs to them. The movie was made in 1976, and is in Spanish. Though I am an American, I do not speak that language, so I'm sure I missed some of the subtleties in the scene, but on the other hand, there's this "universal language" thing that's going on, which makes it pretty easy to figure out.
The visiting wife, or girlfriend, is taken to a room to be searched by a prison matron. "Off with Las Ropas" she says.
"Skirt too. Ahora, por favor."
"No need to be shy, sweet cheeks," the matron says, " las Pantaletas too."
The matron half heartedly paws through the clothing of the young mujer. She's far more interested in searching somewhere else.
She dons the rubber gloves.
The matron conducts a slow and careful cavity search, bringing it to a thoroughly satisfying conclusion for both participants.