John was a pathological philanderer. One day he was boasting about his sexual conquests and told Hal that he was currently dating two sisters.
“Both at the same time?” asked Hal.
“Well, not together,” replied John. “I visit them at different times so they don’t suspect they’re seeing the same guy.”
“You sure are a piece of work, John! How long do you think it will be before they catch you this time?”
“I dunno,” said John. “I’m surprised they haven’t figured it out already considering they both live in the same convent.”