An elderly priest had become so forgetful that he found it hard to remember all the sins that had been confessed in the long sessions common amongst some of his more active parishioners. To help him set the correct penance, he used to take a stick of chalk into the confessional and mark the sleeve of his cassock for each sin confessed with one or more lines, depending on the depth of the transgression.

One day, a young man went into the box and said "Father, I went to a dance last night"
"Oh did you now?" said the priest, who chalked up a mark on his sleeve.
"And I met a girl" continued the young man.
"Oh did you now?" said the priest, chalking up another mark.
"I took her outside into the moonlight, Father"
"Go on", said the priest, adding two more marks to his sleeve.
"Well, …. I made love to her in the car park"
"Oh DID you now?" exclaimed the priest, adding five more marks. "And who was this young woman that you led into temptation with your lust?"
"It was the Vicars daughter, Father"
"Ah, boys will be boys" sighed the priest, rubbing the chalk marks from his sleeve.