Literally any discussion about Pokeyman (or Yugioh, etc.) our parents overheard was complete nonsense noises to them. I've had this brought to my attention by my mother, but only as an adult.

Also, anything we picked up from our era of flash videos - e.g., someone saying "so, this is the ....What a sweet you might say" and someone else reflexively responding "round", or a loop of "badger" and "mushroom" between friends: also nonsense.

In any case, it's an important skill to learn the new slang: as an old, it gives you the power to make it "cringe" by using it. Very fun, on god