"Lost Tribe" joke

An explorer is searching in the Amazon jungle for this lost tribe whose women are reputed to have vaginas that are three inches wide and twelve inches long.

Finally he finds the tribe and is invited to sit down with the chief.

"Is it correct," he says to the chief, "that your women have vaginas that are three inches wide and twelve inches long?"

"That correct, man," says the chief.

"However do you manage to have sex with women with vaginas that are three inches wide and twelve inches long?" inquires the explorer.

"The chief looks at him as if he were an idiot and says, "They stretch, man. They stretch!"