Question

Explain the irony ? "I showed them the toothpaste all right

Answer 1

opposite to the real situation is the irony

Answer 2

These lines mean that when the poetess was told by her parents to brush her teeth, she would show them the toothpaste but she would not brush her teeth with it. It is ironical that she would put the paste on brush but instead of brushing her teeth she would wash it off. And now she repents doing it , she wishes that she had listened to her parents.