What it is
You’re about to say what you actually want, and right then out comes the “lol,” the “I’m just another idiot,” the “or not.” The self-deprecation arrives exactly when the want would become visible. It looks like humility. It’s armor: if you never fully say it, nobody can turn it down.
How it shows up for me
I do this constantly in writing and in texts. Now when I see “lol” after something I care about, I delete the “lol” and leave the sentence standing.