You should never make jokes about vaginas...
Period.
Why does the bar association forbid lawyers & clients from having sex?
To prevent them from billing twice for essentially the same service.
One night my wife tried to get a rise out of me and make me jealous. She asked: "Honey, what would you say if I was having sex with your best friend?"
I told her: "I'd say you're a lesbian!"
And that's when the fight started...