Contagious

At school one day, Little Johnny's teacher asks the class to use the word "contagious" in a sentence...

Cindy raises her hand. "Yes, Cindy?" She answers, "I was at the dentist's office with my mom, and she said not to play with the toys in the waiting room because the other kids were contagious."

"Very good, Cindy!" the teacher said, "Anyone else want to try?" Samantha raises her hand. "Yes, Samantha?" She answers, "My dad tells me not to yawn because then everybody else yawns. He says yawning is contagious."

"Excellent work, Samantha! Very creative," the teacher praises. "Okay, one more volunteer." Little Johnny raises his hand. "Yes, Johnny?"

"Well," he says, "I was helping my dad in the yard last week, and we saw the neighbor painting his house. He was using a small brush, so I asked my dad, 'Daddy, why is he using such a small brush?' and he says, 'I don't know son, but it's gonna take that contagious.'"

*OP's note: for those that don't get it... sound it out in two syllables.