A patient was waiting in a pre-op room for his vasectomy. A nurse walked
in, lifted his robes, and gave him a blow job. The patient exclaimed:
Hey, that was great, but why? The nurse responded: The doctor likes
your tubes to be flushed prior to the operation. As the patient was being
wheeled into the operating room, he noticed other patients masturbating.
He asked the attendant why they were doing this. The attendent replied
that they, too, were about to have vasectomies. The patient then inquired
why he got a blow job, while they had to masturbate. Simple, said the
attendant. They have HMO, while you have Blue Cross.

Paul Blumstein