"Knock, knock!" he called in a high, singsong voice.
For a moment, silence. Then a thud and a crash, as if something heavy had been hurled at the door. "Go away!" snarled the voice from within.
Ah, no. That's not how the joke goes," called Rob. "I say 'knock, knock', and you're supposed to answer with 'who's there?'"
F*** off!"
Nope, that's still wrong." Robbie seemed unperturbed. I, however, was horrified at Ethan's language, though I knew it wasn't him. "Here," continued Rob in an amiable voice, "I'll go through the whole thing, so you'll know how to answer next time." He cleared his throat and pounded at the door again. "Knock, knock!" he bellowed. "Who's there? Puck! Puck who? Puck, who will turn you into a squealing pig and stuff you in the oven if you don't get out of our way!" And with that, he banged the door open."