"Magic Apple" joke

A young fellow ran into an old man who was carring a bag.
"What's in the bag?" the youngster asked.
"magic apples", the old man replied.
"Prove it", said the young man.
"Well, besides apples, what is your favorite two fruits?" asked the old man.
"Watermelon and peaches", he answered.
The man handed him an apple and told him to try it out. The boy took a bite and said that it tasted like a watermelon. "Ok, turn it over", he said.
The boy did and took another bite and said that it tasted like a peach.
The youngster still wasn't convinced that they were magic.
The old fellow told him to name something else that he liked to eat.
"I like to eat pussy." he snapped.
The man handed him another apple and told him to try it.
He took a big bite, spit it out, wipped his mouth and esclaimed, "That tasted like shit".
The old man looked at him, smiled and said, "Turn it over."