The teacher in class asks riddles

The teacher in class asks riddles.

She asks little Johnny:

“It’s a small animal with 4 legs. What is it?”

Little Johnny says: “Dog.”

The teacher replies:

“But could be a cat too. Alright, another one. It’s a long, thin animal with no legs.”

Little Johnny: “A snake.”

Teacher: “Could be. But could also be an eel.”

Little Johnny: “Alright, I have a riddle for you. When you put it in, it’s long and hard. And when you take it out, it’s small and wet.”

She turns red and slaps little Johnny across the face.

He then smiles through his painful grin and replies:

“Could be that, but usually, it’s chewing gum.”