Pluck out the nanner at the base. Even if you pull out a bit of flower too, it's important to pull it out intact. If it bursts, it may be game over.
I had my last plant throw up about 10 nanners in its last 10 days of flowering. I carefully plucked them all and it never pollinated. The more white hairs, though, the easier it is for her to seed. If you have a lot of other plants, it may make more sense to pull the entire thing. In my case I only had 3 so it was way more beneficial for me to save it.