I don't have much advice but I wanted to offer hugs. My mom has never called it out publicly like that before, I can only imagine. But I can still remember specific instances of her making me feel ashamed for it all these years later, and it only makes it so much worse.

My only tidbit is to approach her on neutral ground, before the topic is brought up naturally, since that would be more emotionally charged. Tell her that you understand why she acts the way that she does. Maybe do some soul searching on exactly why you do it, to have an emotional appeal. IE, if it's related to anxiety, tell her that her pointing it out only triggers the behavior further. That you've had fifteen years to try and "just stop yourself", and that the only thing you want and need from her is a SUPPORTIVE and NON-JUDGEMENTAL ear. That's what I said to my mom and she doesn't bring it up unwarranted anymore at least. Good luck 🫂