Joke: IM Holding Somefin-Fool joke

A teacher was playing a game with her class. She said "I'm holding something behind my back. It's red and you can eat it." 

A little boy puts his hand up and says, "Please Miss, is it a tomato?" 

"No," replied the teacher, "It's an apple, but it shows you're thinking!" 

She continued, "I'm now holding something behind my back. It's yellow and you can eat it." 

A little girl puts her hand up and says, "Please Miss, is it a banana?" 

"No," replied the teacher, "It's a lemon, but it shows you're thinking!"

Just then, little Johnny at the back, giggling putt's his hand up and says, " 'ere Miss, I got one for ya! I'm holding somefin' under the table. It's straight and 'ard, two inches long and got a round red bit at the end!" 

The teacher says, "Johnny, don't be so vulgar!" 

Johnny says, "It's a match Miss, but it shows you're thinking!"