live something like that down??
“Anyone want a Nick Eisner?” Nora asks.
“Are you serious? Yes. Go get the peanut butter,” says Alice in her bossy voice.
A Nick Eisner is a cookie with a random glop of peanut butter on top, because when we were five, Nick thought that’s what people meant by peanut butter cookies. Admittedly, they’re delicious. But in my family, you never live something like that down.

I would like to know what does " live something like that down" here mean? Forgetting something like that ??

Question

live something like that down??
“Anyone want a Nick Eisner?” Nora asks.
“Are you serious? Yes. Go get the peanut butter,” says Alice in her bossy voice.
A Nick Eisner is a cookie with a random glop of peanut butter on top, because when we were five, Nick thought that’s what people meant by peanut butter cookies. Admittedly, they’re delicious. But in my family, you never live something like that down.

I would like to know what does " live something like that down" here mean? Forgetting something like that ??

Answer

The phrase is usually said in the negative with "not" or "never".  If you do something silly or embarrassing and other people see you do it, then you can expect those other people to remind you of that occasion in future.

For example: "John, do you remember the time when you tripped in the restaurant and spilt beer all over a customer at the next table?" John probably wants to forget the episode but his friends who saw it will make sure that "he never lives it down".  Hopefully, it's only a little bit of fun and teasing.