Knock Knock

I tried to teach Jes how to do a Knock Knock joke.

I say "Knock Knock"
"now you say 'who's there?'"

He says, "Who's there?"

I say "Phillip"
"now you say Phillip who?"

He says, "Phillip who?"

I say, "Phillip the gas tank please."

He doesn't smile. He doesn't get it.

He says, "Who's Phillip Boo?"