A businessman and his secretary, overcome by passion, retire to his house for what is popularly termed a "nooner." "Don't worry," he purrs. "My wife is out of town on a business trip, there's no risk."
As one thing leads to another, the woman reaches into her purse and suddenly gasps, "We have to stop, I forgot to bring birth control!"
"No problem," her lover replies. "I'll get my wife's diaphragm." After a few minutes of searching, he returns to the bedroom in a fury. "That witch!" he exclaims. "She took it with her! I always knew she didn't trust me!"