The term “bags” refers to the amount of cryptocurrency you are holding. For example if you have a million Dogecoin, you are a fairly large “bag holder” of that specific coin.
You may also hear things like, “don’t fall for this, he is just trying to get you buy his bags” – implying that someone promoting a project may be trying to get you to buy in, so they can sell and leave the project.
Being a bag holder isn’t necessarily a bad thing, if you believe in the project’s long term growth. Just don’t get caught in a dead project, left behind “holding your bags”