Both are a play on words.
Very carefully
Because she uses the other one to sing.
You: You can tuna piano but you can't piano a tuna! Person getting told joke: What about the jar of glue? You: I knew you'd get stuck there
Al-redi-reddi-tt.
Because they don't know the words.
Because they'll always have the last word.
The thesaurus.
ME: I want you checking thesaurus in a panic haphazardly
