How has Liza not learned

Never say a catch phrase or slang term if you don't know what it means. I know she was trying to sound young when she used the phrase 'slide into your DMs' but she had just heard the phrase that morning and was not completely up on what it meant. Kinda like people saying netflix and chill and thinking they're saying watch a show and relax.

Also, I would think if you were trying to pull something like this off, you would have urban dictionary at the ready on your phone so you can check out what things mean.