Just don't tell her any funny jokes...My wife's vag? Who the hell knows. Giving it some space at the moment.
Unless she's wearing TWO pairs of pants and a Tena-Lady!
...or better still, wait till you're both in the middle of shopping.... or at a friends' house, then tell her THE FUNNIEST JOKE YOU KNOW... then sit back and watch hilarity ensue!!!
You're most welcome!
(One for the Dad's there...)