Scratching down there

Hello,

In my sleep, I scratch down there, mostly my labia and not inside my vagina. I don’t know why but I’ve done it for years. Recently I’ll scratch hard enough to bleed or cause abrasion and I don’t know how to stop.

If I am awake I’ll stop doing it but I don’t know how to stop my sleep self from doing it.

I’ve had yeast infections in the past but it isn’t like that. It’s not that it itches normally and no strange smell. I’ve been tested for STDs (negative) and have had the same partner for 6+ years. There’s no bumps or bug bites

Any idea why I do this or how to stop?