A priest, in complete violation of his celibacy wows, makes amorous advances to a nun who, at first, rejects his proposals saying it's a sin, but finally relents and the two end up in bed together.

After making love, the nun says, "Since you are a priest, I would like you to hear my confession. I have sinned. Twice."

The priest says, "What do you mean, 'twice'? We only did it once."

The nun: "You're going to do it again, aren't you?"