"Gaining a little weight are we sister Susan?" he asked.
"No, Father. Just a little gas," Sister Susan explained.
Three months later the priest noticed that she had gained even more weight. "Gaining some more weight are we Sister Susan?" he asked again.
"Oh no, Father. Just a little gas," she replied again.
A couple of months later the priest noticed Sister Susan pushing a baby carriage around the convent.
He leaned over, looked into the carriage and said, "...Cute little fart."
Speaking of nuns......
Nice stools, ladies!