I've googled this a bunch of times and everytime almost everything said it was not true. The vagina stretches for more comfortable penetration and then it ALWAYS goes back, like a rubber band. From what I've read, the only time there is permanent stretching is during child-birth. And to make it tighter you can flex and unflex your vagina muscles to bring the bones (I think) closer together for a tighter grip. They're called kegels if you didn't already know