One day Little Johnny is in class, and his teacher assigns him to make up a sentence and a word for the letter F.

So the next day when the teacher asked him to read out his sentence and word he chose he replies with,
"The word I chose was FASTENATE."

The teacher very amazed by his big word gave him a round of applause and then she asked what the sentence was and he replied by saying,
"My sister has a red sweater whit nine buttons but her tits are so big she can only FASTENATE."